“The Objective 2 is an open source amplifier designed with emphasis on benchmark performance and low cost”, that’s how the O2 is described by JDSLabs, the makers of the C421 portable amp we reviewed a couple of weeks ago. JDSLabs and Epiphany are, as far as I know, the only two bigger O2 “dealers” and they were kind enough to supply us with their version of the banned Head-fi’er Nwavguy’s O2 amplifier.
Lots of people consider the Objective 2 to be a portable amp, mostly because it can also run on rechargeable 9V NiMH batteries but mesuring 108,50 x 80 x 29.5mm you can hardly call it a real portable amp, it’s more transportable as it is portable. I don’t see myself taking out this amp during public transport, but hey this is coming from a guy who doesn’t use full size cans in public either. Anyway, I categorised it under “Desktop Amps”.
The designer, Nwavguy, is about mesurements, and Headfonia is, well, let’s just say we’re not. We use our ears the way we always use them in our reviews. This is our way of reviewing, you like it or you don’t, so please don’t start about Nwavguy’s Objective and Subjective Challenges, etc. We are just giving our idea of the O2 amplifier and don’t have any intention to disrespect the designer and his development/review methods used.
Just like the C421 this amplifier has the input and output jacks, both 3.5mm, on the front just like the power button, gain button and even the AC connector. The Objective 2 uses an ALPS dual Analog Potentiometer which I think is great, I can’t say anything wrong about it in this design at all. Inside there are two JRC NJM4556AD Opamps and one JRC NJM2068D Opamp but I’ll let Mike talk some more about the technical aspects.
To start, the O2 amp is dead silent at all time, there is no hiss whatsoever (not that I expected it to) and turning the ALPS pot doesn’t make any noise at all. You immediately notice the big soundstage this amp has and its transparancy. There is no coloration what so ever, it is very neutral sounding and has a lovely detail retrieval for a mini amp. And with the excellent balance and instrumental separation it also has it makes it one, if not the best amp of that size I have heard so far in regard to these specific characteristics. The Objective 2 has more power as you’ll ever need (Dual Gain Switch (2.5x and 6.5x)), as a matter of fact I never had to use the highest gain setting, of course I did, but it wasn’t necessary. I know that JDSLabs offers to modify the gain settings to your liking when you order, I’m not sure if Epiphany also does that but it’s good to know in case you have a special headphone laying around you think will need an adjustment.
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haha the 4th paragraph got me giggling, especially later on when mike compared it to the asgard XD
Interesting review guys, thanks for the write up, enjoyed reading this quite a bit since i was well…. ill stop there.
That actually is a coincidence. really. Don’t stop, tell us what you are thinking
i think mike covered what i was thinking quite well in his section, the whole technical not necessarily translating to what you get. Personally i was moderately skeptical about this amp, yet very amused by his project. I have to say though, it is still a some what interesting product.
On a side note, his current project is actually much more interesting…well to me at least….
Yes I had no idea the Asgard was so closely related to NwAvGuy. I was just comparing it based on price, it’s the closest priced desktop amp I can think of.
Pg. 3: ”
The chassis is too light and it moves around a lot. ”
It should be noted that we now include a set of stick-on bumpers (feet), so the O2 can’t slide around. Headfonia’s O2 sample shipped before we spotted this inconvenience…
I agree, I put them on my C Moy and 421 and they stay put.
Almost missed this in comments – can you stick it as a note in review please?
Made the change on the review. *thanks L*
Yes that should help a big deal. Thanks, John!
That’s quite a bummer. No synergy with the HD650? Anyway, I’ve heard people over at Head-Fi say that it’s literally the second coming of cheap amplifiers, as its glorious sound really outweighs its price point. After reading this review I can now see some of the potential caveats and it looks like the O2 may have been a little overhyped and farfetched.
I’d try it out before you dismiss it after one review. I like the reviews here but this just seemed like a review to generate page hits.
Well as I’ve said the clean black background is indeed very impressive, and a lot of people do enjoy that aspect immensely. It’s like listening to a planar headphone: clean grainless black background.
It was the same feeling as when I first heard my pair of Fostex T50RP’s. Black. But now I can have that feeling with the Z1000 and the AD2000 :3
But… my Fiio E10? Is more musical of THIS??
However… if it’s absolutely neutral, O2 + Beyer 880-600 ohm is the king of monitoring 😉
I’ll remain with my Fiio and Hd598…
But O2 + Hd598… how it sounds?
I didn’t feel the magic with the HD598.
Uh oh… my HD598 is recabled, though, with a Cardas 4×24; it sounds a little different from the stock.
You are just saying this because you don’t want to tick of your sponsors by saying this amp is better then amps many times the price. You guys are clearly bias and have let the price dictate what you say. In a blind test, you couldn’t tell the difference. Not that I believe this, but I figured I would save Nwavguy and his groupies the trouble and post it for them. Sad this isn’t a more musical amp
Sad cynical dude are everywhere on the internet these days.
You had me fooled there for a bit
And those measurements dictate your brain not to trust your own ears.
Yeah, right.. -__-‘
Trent was being sarcastic there, sicgoat. 🙂
Ears are easily fooled and untrustworthy as devices. Eyes and memory are likewise. Eyewitnesses of events have proven many many times untrustworthy. Memory changes the shape of a room, the color of a car, what someone wore, the first letter of a name (as in “I can’t remember but it begins with a J, only to find out it was Paul).
Ears are important, yes, even untrained ears can tell the difference between “Live or Memorex”. However, ears are not very good test instruments and your brain forgets a sound character in mere seconds. While audio can be subjective in regards to instruments, headphones and speakers (I just don’t like the sound of a steel guitar) the electronics used to drive those acoustic peripherals should add as little change to the signal as possible (Do No Harm To The Signal).
While all electronics (and speakers to a far greater extent) add “something”, some designs like the Benchmark, Violectric and the O2 in particular, their additions/distortions are below your perception threshold and are so-called “transparent”. A colored amp or preamp is like having tone controls or EQ that is always on and ever changing depending on what you plug in. Is that really how you want your electronics to be?
To me, “synergy” is an ill-formed amorphous word people throw around when Product A & Product B just happen to sound good together. You cannot tell anyone that either A or B will sound good with C. That’s a crapshoot. With transparent electronics, you can be assured that the sound you hear is the basic sound character of your headphones (a whole other matter).
Not all audiophiles like the Senn HD650’s and perhaps someone (Mike and/or Lieven) doesn’t like their true nature when hearing through a truly transparent amplifier. Point being, if you want to add some EQ or tone to a recording, so be it, use it and apologize to no one, at least with transparent electronics you can turn it off when no longer suitable.
The fundamental problem with the review is not that the O2 was regarded as “meh”, it is that IF Mike truly likes the Violectric V200 (a measurably transparent amp) or the Stereophile “Class A” rated Benchmark DAC1 (another transparent amp) and NOT expectation bias, he should have held the O2 (a measurably transparent amp) in the same regard to a great extent. Then all transparent amps should be regarded as “meh” by Mike/Lieven and since this is not the case, it is tantamount to intellectual dishonesty. At this point, how can any of their reviews be considered accurate and/or honest? This is the Pandora’s Box of subjective-only reviews because neither Mike nor Lieven can reliably recall from memory the sound of any amp they have ever heard. The brain just does not work that way.
“some designs like the Benchmark, Violectric and the O2 in particular, their additions/distortions are below your perception threshold and are so-called “transparent”.”
And how do you know that ?
“Ears are important, yes.” — Well, no, they’re not just important. They are everything, without exception. You can provide me machines to measure sound as a guide to my analysis, but that’s it. You can’t have your machines tell me “This is it, end of story.” Do you understand why that is?
“Sad this isn’t a more musical amp” so, you have an O2 or even listened to one? Or are you just propagating the view(s) of someone else? The rhetoric here goes against the vast majority of reviews of the O2. Otherwise, I agree with your post.
What source and headphone did you use for this review?
I used all sorts of stuff.. sorry for missing that out.
Source: Dacport LX, Kingrex UD384, Fiio E10, Ipod, Altmann Tera. Headphones: Gosh so many. LCD-2, HD580, HD800, HD650, Philips Fidelio, MSPro, HD661, HD25-1, ATH M-50, Goldrings, PX100, HD200, Beyer T1, and a bunch of IEMs. I can’t even remember them all.
I’ve had the amps for a few months and so I don’t really keep track of what I tried it with.
I’ve been noticing that some people are remarking that the O2 is lacking microdetail… I don’t need power nor authority, since I have an easy-to-drive HD598 and everything else is universal/custom IEMs, so I really appreciate its ability to convey a black background, but someone tell me I’m not better served by saving up for a Leckerton UHA-6 Mk. II or something… Oh, and I don’t need portability. I never amp on the go.
Sounds like the O2 may be a good amp for you Tom.
Yeah, that has been my suspicion for a while; I’m just concerned about some peoples’ grumblings about not having enough detail as other TOTL amps… should that even be a concern?
It’s not a big concern. You only need so much detail after all.. I was just saying that if we’re going to brand this as a technical amp, it needs to do better on the micro details.
I mean I can listen to a Cmoy and not complain about detail levels.
Do you feel like your perception of the micro-detail is also related to the level of grain? Or rather, a bit of grain adds a bit of ‘sizzle’ to the lower/upper treble, and thus treble micro detail is easier to hear. To my ears, the actual level of detail of the O2 is quite high especially considering there is no noise floor, but the lack of grain means that the treble lacks the kind of ‘edge’ that something like the Asgard has.
That’s my suspicion as well — Regarding: La-chan’s comment
La-chan, if there is one thing with grain and micro detail is that they tend to obscure it. Like on a photograph, a grainy photo can look romantic but you’re not going to see the small details. That’s why Ansel Adams shot his monumental landscapes in low ISO film so you can see the detail.
And on the treble part, I can only say that micro detail is different from treble.
a rough subject. On one hand, there are plenty of measurements saying
that this is “the best” amp. However, do perfect measurements guarentee
it will sound good? Absolutely not. i was just having this convo earlier
about how everyone’s ears are shaped
different, thus having different resonant frequencies, thus having
different preferences for things such as sound quality and IEM’s. Look
at ATH-m50. WAY overblown bass, but some people LOVE it. A friend of
mine demoed my rig. He got REALLY into Stairway To Heaven. When I got it
back, I was horrified: ATH-m50’s with bass boost 2 on Fiio E11. WTF?!
But that is “good” to some people. So is the O2 a bad amp? Certainly
not. Is it the RIGHT amp for the reviewer? Certainly not. However, are
there those who will claim it to be the best amp for them? Certainly.
Sound is both subjective and objective and no matter how objectively
well your amp performs, subjectivity will always bleed into the
measurements. Even if you plug it in and test it on a dummy head, you
wont get any measurements that are worthwhile to a human audience. Its
about trial and error as much as it is about design in the audio world.
Thats not to say design by ear is the only thing to go by. There are
certain measurements that should be guarenteed from a circuit (noise
floor, power down transient, decently flat frequency response) but where
people err is to think that 100% perfect measurements guarentees a 100%
perfect sound. I challenge anyone to find or build an earphone with a
perfectly flat frequency response, listen to it, and tell me it sounds
good to them. Thats not how ears work. Every ear is different, every
mind is different, and everyone will find their own slice of audio
nirvana. The O2 is simply not an end-all be-all solution to amps, and
although NwAvGuy did a great job in design and such he cant design
peoples ears to like his amp. Thats all there is to it.
Just wanted to say, as an O2 owner I think this is a fair enough write-up. Although the O2 measures well and isn’t particularly coloured, the neutrality does mean that you aren’t going to find any special synergies with any particular headphone. In a way, that is both the selling point and the downside of the amp – the thing has been designed to be a tabula rasa of sorts, a ‘blank slate’ amp that will, with its low output impedance and low noise, deliver exactly the same sound to every single pair of headphones you own.
If you have a single favourite pair of headphones, this might mean a swing and a miss for synergy. If you like to collect headphones like I do, you might value the idea that you are comparing all your headphones on an electrically similar level – or rather, the electronics are not holding back any particular pair. No matter the impedance, sensitivity, etc of the headphone (except say some certain exotic models) the amp is going to deliver, and that is pretty impressive for a $150 amp. It means I can spend less time worrying about potential synergy issues and more time thinking about the actual ‘basic’ signature of the headphones I’m listening to. I switched from an Asgard to an O2 because of a low level ground loop or related problem I was getting through the Asgard, and upon the switch I was impressed by the lack of noise and grain in the sound. I’m happy, and I’m looking forward to the desktop version 🙂
I think this is one of the most polarizing reviews you two have ever done and I believe this review is the perfect example of the Headfonia identity. I really loved reading the review exactely for this reason because it illustrates perfectly what audio-enthusiast, opposed to audio-technicians, look for in an amplifier. And dare I say the word I’m looking for is “musicality”? 🙂
This amp is all about the angle from which you look at it. In my opinion, it’s created solely as a proof of concept. I think of it as a grown-up, DIY wire-with-gain. I can’t comment on it’s signature because I CAN’T HEAR the Objective2. It disappears in my rig, completely. It’s a true amplifier. It amplifies my signal (DAC) for my headphones. That’s all it does. And it does that effortlessly.
Compared to other amplifiers out there, I think it’s important to remember that the Objective2 is originally meant to be DIY’ed for around $50 (excluding fancy enclosure). It wasn’t created to be mass produced and sold for $150. Objectively (pun intended) anyone with basic solder skills can build an Objective2. If you understand this, it suddenly becomes a much more interesting product. The intentions of it’s designer were to prove that it’s possible to create a very functional amplifier with a small footprint, for a fraction of the cost of more respected amplifiers in the market right now. One that MEASURES really well too!
Measures… Those brings us to, what I think, is the true crux of reviewing the Objective2. Inherent to an amp that measures like the Objective2 is the lack of colouration and colouration is, like we learned from, for example, tubes and equalizers, an audiophile’s best friend. It’s an audiophile’s dirty secret too. The neutrality we strive for stands paradoxal on the musicality we crave. The Objective2 is neutral and transparent and, as opinions on the O2 show, when we are confronted with true neutrality, it might not be as satisfying to our ears as we thought it was. 😉
Erik, I’ve been meaning to ask you, but how does the O2 compare to the HeadStreamer’s output? I’m strongly considering the O2 as the output for my D7, as I really feel the D7’s output is colored.
Like I said in my previous post, I can’t really comment on the difference in sound signature. I can only say the Headstreamer’s output is more suited for low-impedance cans. The O2 is more versatile in this regard. 🙂
The question that I’m asking really is, is the O2 really the superior design it’s meant to be? I’m referring to the bit where I’m talking about how the amp behaves at high gain.
At high gain, what you were likely hearing was the input stage clipping. High gain is not meant for more volume with sources like the DACPort, but to allow low-voltage sources such as iPods to be boosted to a level to drive difficult headphones.
Doesn’t JDS/Epiphany mention this in their documentation? It’s prettymuch the most common misconception regarding the O2.
Clipping is different than a loss of black background.
I have personally done blind, volume-matched comparisons of the amp clipping and not clipping: it does not necessarily manifest itself as obvious distortion, dependent on the severity of the clipping. Indeed, the abrupt rise of both odd and even-order harmonic distortion products creates an impression of harshness and loss of clarity; However, you don’t immediately go “Ah hah! This amplifier’s input stage is clipping.”
It is reasonably audibly obvious under direct comparison: several people unaware of the real purpose of the gain switch over at Head-Fi ended up with horribly clipping O2s. In each case, they were unaware that their amplifiers were clipping and instead wrote of a mysterious degradation in sound quality on high gain.
I was, however, confused by your mention of rising noise levels. The O2’s noise is completely imperceptible under all possible circumstances AFAIK. If any noise is heard, it must have come from the source.
As I’ve said, clipping is different than loss of black background. What else can I say?
OK, what exactly *do* you mean by a “black background”?
(In response to bottom post by Mike)
“Black background” is like a “dry sound” — it’s applying a term from another sensory realm (sight, taste, etc.) to audio, as if it somehow makes sense. It’s akin to saying that chocolate pudding has a somewhat blue taste with hints of acoustic feedback.
This is the healthiest and most honest comment I’ve read in a while: ” The neutrality we strive for stands paradoxal on the musicality we crave. The Objective2 is neutral and transparent and, as opinions on the O2 show, when we are confronted with true neutrality, it might not be as satisfying to our ears as we thought it was. ;)”Much needed indeed. Cheers!
Very good post. I eschew coloration (distortion) in amps and electronics in general but not opposed to using some EQ on tracks that may need it because I can turn it off when I want to. A colored amp will always bring its inherent distortion (EQ) to any set of ‘phones you plug in.
‘Synergy’ is not a good thing because it is so random. Any combination that has ‘synergy’ cannot be said to work with a different combination of gear. The consumer is left to spend hard earned money on products that may not allow the best performance of the headphones.
Another problem is many (most?) boutique manufacturers can’t even properly measure the gear they make. Or, they neglect to provide the real specs. Look at the fiascos NuForce & Schiit have found themselves in for example. Both of these companies have been caught with their pants down. Inexcusable. Do we even know their engineering qualifications? Unaware consumers led by spurious anecdotal subjectivism spend money on sub-grade half-baked gear thinking they are getting something great.
The O2 has been extensively tested and shown to the world for examination. Even the slightly compromising sections (e.g., half-wave ps) have been disclosed and the rationale behind using it was given. Even so, it has been shown to be utterly satisfactory. Some of the specs even beat out the venerable DAC1 by a good margin. Anyone is free to test the amp on their own and some have, showing the results to confer with the designer. No other amp in the hobbyist world has been under such scrutiny as the O2. The designer would be insane to publish false or misleading documentation, as some here have suggested.
The truth is you need a colored amp to sinergize with a colored headphone, there’s NO one amp that fits all. That’s why it’s better to err slightly on the side of bass / midrange with headphone amps, it’s the compromise that works with most of the headphones on the market.
That’s also why tube rolling is such a great tool for headphones, it’s a easy and non-damaging EQ tool. Most people have no idea how to use actual EQ without damaging the sound, so at least they can use tubes.
So, it’s not the O2 that’s bad, it’s the premise it was built from. If there was a neutral headphone the O2 would be great. As there isn’t, I suspect it’s only good with the ones that get close to neutral, like the HD600, or the ones that err on the side of bass like HD650 and LCD2.
I’m not too sure a mythical “neutral headphone” would be the right way of thinking about this. It would be more “if only there was a headphone that I was completely 100% satisfied with the sound with, and the O2 wouldn’t change anything about it.” Of course that’s a meaningless statement when people’s preferences and tastes for sound change over time, and sometimes even in the same day.
Not only that, people’s hearing changes over time and the mastering style of music changes (degrades) over time. 🙂
That’s not an argument against a neutral headphone (which is NOT possible, even moving a headphone a little over your head completely changes its frequency and phase response).
Tip: if you have a bright headphone move a little forward on your ears, towards your nose.
Lacking bass impact is different than being neutral. Lavry DA11’s headphone out is very neutral but the bass impact is very powerful. Likewise amps like the Beta22.
The DA11 and the Beta22 have a better PSU with more voltage swing, they control the bass better. They might have also have higher output impedance which gives an impression of bass weight (not verified).
We are sensitive to even a 0.1dB increase in sound, well inside the linearity performance of most DACs, nevermind that of amplifiers which is way worse usually. If that increase is spread over a significant frequency range, it’s even more important.
Also, different amplifies have different phase response, especially in the bass region.
The PSU is not a valid excuse since you can get a Cmoy build with 18V that again would have more bass impact than the O2. (though not exactly a neutral sound)
Are you sure that more bass impact is not simply the opamp in a CMOY getting incredibly upset at having to drive low impedance loads directly? Many of the “audiophile” opamps that people opt for are likely unsuited to driving headphones directly.
Are you suggesting that bad pairings = better bass impact? Sorry I don’t understand.
(In response to bottom post by Mike)
Defining it as better or worse is entirely up to you. My opinions on the matter are very strong and unlikely to be perceived as constructive 😀
By the way, did you two have any opinions in terms of which build (Epiphany or JDS) you preferred?
The Epiphany is a tad more solid and is a little heavier.
Ok, here’s my take on the whole subjective/objective nonsense.
First of all measurements DO matter and designing amplifiers/headphones/dacs/… is not an art as some would like us to think. It is a an artisan craft that relies on technical knowledge and repeatable products as that is one of the signs of good craftsmanship. Mike , I think, will concur when I say that the difference between a professional photographer and an amateur is that a pro will always deliver a quality product whilst the amateur has much left to chance. Also the artist seeks to express an emotional message through his production while an artisan goes for quality [re]production.
Returning to the false dilemma of measurements vs ear. Again I will remark that modern microphones and other measurement equipment are far more potent of picking up data than any human ear. Not to mention that equipment leaves out the human factor of hearing. However it takes real human knowledge and experience to associate the measurements with psychoacoustic phenomena. Also it takes some listening experience to associate the documented and agreed upon psychoacoustic phenomena to personal qualia of sound perception (i.e. how does sibilant sound to you?). If we could successfully do that then Mike could just take some ultra nice photos of the gear in question and just slap some graphs under them. Maybe a remark here and there about ergonomics and a review would be done. Everyone could then translate the raw data into personal listening experiences and all would be well. However as it seems from what I’ve seen- there is very little knowledge on how to successfully translate measurements into psychoacoustic phenomena. Otherwise we would not have Nelson Pass designing high THD amps that sound pretty nice and the O2 sounding rather… meh.
Also one must keep in mind that music listening is a purely emotional practice, sure better gear will give you more of the artist’s hard work (not to mention the invisible cohort of tech guys who don’t have the fame and glory they deserve), but it takes very minor annoyances to ruin the listening experience. It might be a nasty ringing in the upper registers or the sense that there’s something better out there that need buying. Or rumbling stomach after that one particular purchase. I’d say for music listening it’s all about happiness if gear can make you happy then it’s good. If it gets in the way of happiness then it must go. For critical applications, however the measurements may reign supreme.
Rudolfs, check out my reply to Erik’s comment below.
Actually a good mic just zooms-in to the instrument better but your ears are still capable of capturing more.
That is quite a statement, what proofs do have to back that up? Are you learned in psychoacoustics and have a medical background? Or, are you just a general know-it-all shade-tree kind of reviewer? I wonder if you would post the results from your own hearing tests, so we can see where your hearing is deficient. Really, what makes you so capable a reviewer? So many points I see made here seem to be off-the-cuff knee-jerk reactions with no real understanding or education in any of the sciences, medical, psychological, engineering. Many have opinions but opinions not based on any real education are not worth much. Beware who you listen to for advice.
Funny thing – when I was a teenager the thought that the entire universe could be squeezed down to something smaller than the head of a pin was unthinkable, absurd, would get you banned from academia forever. Now there are people still clinging to the notion that certain steady-state measurements contain all of the info our ears and brain can detect. And then it gets worse. There’s a small but growing contingent of science that believes our perceptions are not entirely contained in measureable atoms and molecules within our bodies, but may share bigger spaces on the quantum level. These are not witch-doctors any more than the crazies who understood that the entire universe was just a hologram and “solid” matter just an illusion. It does invoke a primitive sort of in-the-mother’s-womb comfort to see people so confident that measurement is beyond human perception in such things as cables and amps, but then reality sets in eventually and we get back to exploring.
It is well known that the best microphone connected to the best amplifier connected to the best speaker, cannot reproduce a musical instrument accurately. We know this by comparing to the original instrument.
This is all that Mike was saying.
People who listen only to electric music (rather than acoustic music) might not be aware of this.
What Mike said was this “…your ears are still capable of capturing more.” My statement stands as is. He shows no proofs of such a thing nor a statement of his own hearing acuity.
Is it good for dubstep, rap , or heavy metal? Thats what i listen to. *falls on floor laughing hysterically making baby goat noises*
Video, or it didn’t happen
Conduct a several loop recording test, if the O2 is being a plain “wire-with-gain”, then it should be compared to a plain “wire-WITHOUT-gain” and see/read/hear the difference refer to the original track. Of course you need a “transparent” DAC/ADC and DAW setup to get the job done.
Actually unaltered recording, if you just listen to it from straight from the mixing console, is always very close to the real thing. Problem is that any recording is always bound to have far more colorations than the majority of amps.
What’s the output impedance of the Asgard? If it’s too high for the phones then what you are hearing is a bass boost at the cost of losing bass tightness and extension, plus a likely treble roll off. Boomy and flabby, in all likely hood, compared to an O2 with a bit of bass boost equalisation (with a decent equaliser, ie. not the ipod but rockbox is good), tight and crunching. I do this with my etymotic HF2 and my modded Fostex T50rp . Excellent results.
That bass boost, if that’s what’s happening, is going to give poor quality bass compared to an O2 with good equaliser bass boost (ie. on rockbox try low-shelf 80Hz +3db q=1. Withm y etymotics I et great bass with no discernible distrotion at +6db
The Asgard used to be listed on their website with a 1 ohm output impedance figure. At some point this published figure was removed and has not been replaced, and its hard to say whether the figure was removed because:
a) It was a typo (seems like a rather unlikely typo to have on the website for a few months. I am not sure if the spec was also listed in the manual as I no longer have mine).b) It was an incorrect measurement (this is troubling if a basic figure can be measured wrong).c) A 1 ohm figure makes the 1.5ohm figure of their upcoming mid-fi amps look a little awkward.
As my main headphones are HD 650,I sold the O2 after 2 weeks of trying hard to like it!The amp is JUST amplifying and doesn’t add anything of the things I like ,be it detail retrieval,being engaging etc. Add to that the lack of punch/bass and you have the O2.Great measurements apparently but sounding like a DEAD DUCK to my ears!
Hype of the Year!
I agree, the HD650 is no fun with the O2
What about genre bandwidth?
Julio Cesar B
O.k I’m here sitting and agreeing with the people that is saying this amp doesn’t sound exciting with 650’s.
Now, I plugged my AKG’s 272 HD and boy, that was jawdropping. I was actually hearing bass punch out of those that i never experienced before except when I plugged them to some Audio Technica HA5000 which is 10 times more expensive.
Then I quickly reach for my 701’s and… guess what. yeah, audio bliss.
This actually has me confussed because as a matter of fact, I always liked the 650’s over the 701’s.
This amp really has some strange sinergy with the AKG’s I can’t really describe.
The goal of the amp, or at least the objective approach, is to avoid creating any sinergy at all. I’m not saying this won’t match perfectly with some pair of headphones out there, and it probably does, but that’s not the point. An amp is supposed to amplify a signal without adding anything.
But to get amp like this with just $100 or less, hmmm.. good item to have isn’t it.. can’t complain more…
but yeah.. it’s not as good as people keep talking out there… HYPE!!! especially people who said that O2 can beat a desktop amp with higher price… it doesn’t have a big sound that I get from a real desktop amp, but for small sensitive IEM it’s actually good..
I have O2 with black PCB…black enclosure… so cool.. decided to keep it… 🙂
My experience with the JDS O2 is similar. With the HD-800 I thought it sounded very good, but with the lesser-bass headphones like the Shure 1840 and 940, the Beyer DT-48A and DT-1350, and a few others, not so good. The treble became harsher and the bass leaner when it was already pretty lean.
Well, I’m enjoying the O2 with my DT48A, at first I felt the Meier Arietta was on par, but it seems that the O2 is not as limited in the frequency range span. I have also tried them with my DT48S Nagra and you can only imagine what i hear. Very Hi End sound. Simply amazing….have been posting less and enjoying the music more since i got the O2.
Being the experienced reviewers that you are, you would of course have no difficulty in repeating these observations in a blind listening test, right?
if the amp really lacks “musicality” and “micro detail” how come no one has taken the DBT challenge proposed by nwavguy himself? if the amp really sounds so different it surely would be easy to identify by sound alone.
The O2 is built off of sound science. Unfortunately, music is both an art and a science. Nwavguy not only left out the art part, he ignores it’s relevance altogether.
Music is an art, and we should leave that to the artist (musicians).
Amplification of signals is NOT an art, at least not if what you look for is fidelity to the original signal.
Not necessarily. How do you explain people’s love of tube amplifiers. They inherently add distortion, but in a musical way.
Music is to provoke a human emotion. If the O2 comes up flat then it is not musical. Some people strive for measured accuracy…great. But others want to be moved by their music.
If you simply want a calibrated instrument, the O2 is your choice.
at least not if what you look for is fidelity to the original signal. ”
if you need distortion to be moved by the music you hear that’s fine, but you should know that you are actually loosing fidelity to the original recording.
I’m simply stating that “a wire with gain” is not everyone’s ultimate goal.
Kinda like spending time with Spock. He’s interesting and scientifically logical, but I wouldn’t want to live with him.
Live long and prosper. 🙂
You are right: _music_ is to provoke a human emotion, but if you need coloration, distortion etc. to provoke that emotion I’d suggest switching the artist, not the amp. Else your own statement doesn’t make any sense.
I am referring to the presentation of the music.
Sometimes it’s just that intangible thing that gets your toe tapping. When you get a system right, it’s easy to tell. On Headfonia they sometimes call it PRAT.
One must also look at the overall system as well. I’ve tried it with my Sennheiser 650HD as well and it’s just not for me. (My comments on the O2 mirror Mike’s). But on other phones, it could definitely be a good match.
Not bashing those in favor of a scientifically, perfect neutral tone, it’s just that unless you are recording your own live, acoustic music, I’m not sure it’s going to happen. Personally, I like the Sennheiser house sound for headphones, but for full size speaker listening I prefer a more neutral sound.
Everyone has their overall system goal. I just don’t think everyone’s ultimate headphone setup necessarily sounds, by definition, perfectly neutral. If it were, then we’d be throwing out most of the “ultimate” headphones available today.
(The like below was me trying to reply to Scott.)
So you’re saying that it’s the presentation of the music that is to provoke emotion, not the music itself? I wholeheartedly disagree.
What makes me toe tapping is the music, not the (re-)presentation/reproduction or the gear. Whether I listen with a nice headphone setup or a kitchen radio doesn’t change if I like the music or not.
What is not going to happen? A neutral reproduction of what is on the recording? Oh it certainly is. You have to differentiate between what is on the recording (the music, the art …) and what is happening between what’s on the recording and the sound reaching your eardrums aka reproduction.
This reminds me of the misunderstanding many seem to have with EQing. When I say I use an EQ, many people ask if I’m trying to fix flaws on the recordings – no, absolutely not. I use a fixed EQ curve for a given headphone that stays the same regardless of the recording, so all I fix are the flaws of the headphone (reproduction), not the music.
It’s obvious that not everyone is into neutral reproduction, and that’s great because there are headphones with intentionally boosted bass or treble and so on and effects processors, DSPs such as EQs etc. But building a reproduction chain with “flawed” components (a DAC with treble roll-off, noisy, non-flat, distorting amplifier, expensive silver cables trying and failing to brighten up the sound again …) is just a stupid way to waste money.
I think I’ve been misunderstood. There are many factors that make a musical experience special. Presentation is just one of them, of course.
I’d like to say that the O2 is extremely impressive when you look at the measurements. So why isn’t it working with the 650HD? Hmmmmm…
I guess what I’m trying to nail down is the “synergy” and emotion in a musical experience. When you listen to music, what is it that makes your toe tap, gives you goose pimples, and just plain puts a smile on your face?
I can appreciate a musician whether I hear them on my headphone system or a clock radio, but a clock radio doesn’t put that smile on my face, much less give me goose pimples. Why is that? Do scientific measurements play a part? Absolutely! But once you reach a certain level of audiophile quality, synergy comes into play.
Does synergy come into play for everyone? Maybe not. But once you feel an emotional connection to your music, it’s wonderful.
Can synergy be scientifically measured? I’m not so sure. How do I know I like a certain food. Do I only read the nutrition label and ingredients? Will that tell me? What’s your favorite color…blue? How do you know? Have you ever been in love? Can you measure that?
If you’re getting synergy with a neutral/uncolored presentation….great! But others don’t. That’s one reason tube amps and opamp rolling are popular. Some people call it “preference over reference”.
If you’re going after a perfectly neutral system and presentation, once again, unless you’re recording your own live acoustic or vocals, your store bought recordings ARE colored. As best, you are getting the artist’s intention. Which I can fully respect.
My loudspeaker system has been calibrated using Audyssey MultEQ XT32 with a Pro Kit using the full 32 measurements. It measures flat and I thoroughly enjoy it as my main course. But listening to my headphone setup is my dessert and I have chosen a warmer Sennheiser based bias.
Again, for many people, it comes down to the synergy of their system. For me the combination of the O2 and the 650HD don’t work, but other headphone combinations could be wonderful.
NwAvGuy designed the O2 using the HD650 and compared it with other people to the DAC1. The lack of “synergy” you’re talking of does not exist. My guess is it’s a lack of coloration or distortion or high output impedance or a combination of the former that you experienced. Or maybe the HD650 just isn’t the right headphone for you, dunno.
“…the lack of synergy…does not exist…”
Wow, that’s quite a subjective statement. If the O2 is purpose built off of measurements, how’s that measured?
I absolutely love my 650HD. I’ve tried them with many amps and have not found them lacking in the least. It’s truly reference headphone.
Nope, it’s not quite subjective. You might want to read up on some O2 articles on NwAvGuy’s blog before continuing this discussion, otherwise you wouldn’t be asking how to measure an amp’s ability to drive headphones or ask for specs or graphs. And before you ask for independent measurements: Google is your friend.
Yes, I’ve read his blog.
I’m not questioning the O2’s ability to properly drive headphones. Let’s keep this discussion on course.
I’m stating that the O2 has no synergy with the 650 HD. You said “The lack of synergy you’re talking of does not exist.” So, if you’re trying to prove your point scientifically, do it.
Let’s get scientific. Charts, graphs, and third party verification or it didn’t happen. Otherwise it sounds like common internet hearsay and therefore subjective by definition.
So the question is quite valid and still stands.
>I’m not questioning the O2’s ability to properly drive headphones.
But in the next sentence you claim it has no synergy with the HD650? This makes no sense. You talk about synergy, yet you don’t even seem to know what exactly you’re talking about. The O2 has ~0.5 ohm output impedance (no need to measure this, look at the schematic) and therefore does not alter the frequency response of the HD650’s due to their non-flat impedance (it doesn’t add bass like many other amps would). Measured frequency response is flat. Distortion has been measured to be lower than a beta22 (not by nwavguy, but I’m not going to do the Google search for you).
What question still stands, how to measure synergy? Here’s my answer: If you don’t know what synergy is, cannot define it or it only is in your head, how do you expect me to come up with a measurement for it?
Let’s be honest. Saying it has no synergy is a subjectivists way to say “I don’t know.. I don’t like this amp”.
Actually, I do know what synergy is. I explained it in a previous post below. Please reread.
A set of headphones can certainly be driven properly and have no synergy. I use the O2 as a prime example. Others on this site agree as well.
I don’t see where you explained it, you just said something like either there is synergy or not and are not sure if it can be measured.
To me it seems that “synergy” is a certain amount of coloration or distortion that makes certain recordings or headphones sound different (of course always nicer subjectively). From that standpoint I can see how you’d talk about a lack of synergy.
Still has nothing to do with accurate, neutral reproduction which this amp is about.
It seems there are two ways to build an audio reproduction chain:
a) Using components whose colorations (objectively flaws) make up for one another (subjectively synergize) that result in combination with the headphones in a objectively inaccurate but subjectively nice sound. You don’t hear every detail that’s on the recording, but a subjectively prettified version.
b) Using components that are flat, neutral (subjectively boring? lacking synergy?) that result in an accurate reproduction chain (excluding the headphones). The headphones plus optional EQ/DSPs are used for the desired (distortion-free) coloration. You hear every detail that’s on the recording with whatever tonal balance you chose.
Well, I’m glad that we can agree that there’s more than one way to build one’s system. It all comes down to choice and what the engineer’s goals and listener’s goals are.
Guess that’s why there’s more than one flavor of ice cream.
I think choice is good when I have a clear choice. But does a manufacturer of a device that’s intentionally made colored to please certain users who somehow “know” about those colorations bother to inform the rest of us who don’t want colorations that his/her design is deliberately colored? My guess is no. My guess is they don’t want to advertise that because it would make them look stupid. I think an amplifier that has “flavors” like ice cream is an absurd notion. Personally I don’t even know of any. I have headphones that are bassy, bass-light, midrange-centric, etc. And obviously so. But all of my amps sound flat and measure flat. Did I miss those bass-heavy amps somewhere? I want to be sure of where they are, because I sure don’t want to buy one!
It’s not the job of an amp to produce music, it’s to accurately REproduce it. If you aren’t moved by your music when played through high-fidelity audio equipment (i.e., equipment that does not color the sound), blame the performer, producer, and engineers.
There is a propensity of some audiophiles to wax nostalgic and think back to a time when tube gear was prevalent. It invokes certain emotions they may find favorable. Tube distortion is definately NOT musical, ANY added distortion is NOT musical. Musical instruments (non-electronic) do not create distortion. It is the reproduction chain that creates distortion artifacts. The O2’s distortion is below you ability to hear it. It is magnitudes lower than tube gear.
The O2’s distortion is below most people’s ability to hear it with the music tracks they have. You have to be sure that applies with higher resolution tracks, or be sure you can’t hear the higher resolution. I’ve made that mistake.
If it were true that ” Tube distortion is definately NOT musical,” then
all guitar amplifiers used on platinum rock albums would never have
existed, and the whole history of rock music since the 60s would never
have existed either.
If we are talking about music reproduction, then the reason people think
that tube amps “sound good”, is because they add back harmonics lost
previously in the chain by some less than perfect components.
For a site that values listening tests and eschews measurement comparisons, I’m troubled by the lack of ABX testing. With the amount of money spent on headphones and amplifiers, a simple ABX box would seem to be essential for comparing amplifiers. This perhaps could be more revealing of differences between amplifiers, but it’s also possible that you would wind up not using it, as suddenly many good (i.e. non-distorting) low output impedance amplifiers would sound exactly the same. Can you offer an explanation for NOT using ABX as a tool in your toolbox (other than you’re afraid it will invalidate much of the differences between amps that you hear)?
As for the lack of bass, assuming it’s not a psychological bias effect stemming from the description of the design goals of this amplifier (“objective,” “measurement-based,” etc.), leading you to expect thin bass and “analytical” sound, it seems more likely that it is a result of the O2 being compared to amplifiers with higher output impedance, causing a boost in bass response in headphones with an impedance bump in the low frequencies. This is a result of the multiple problems with high output impedance, not a fault of the O2. The O2 has been measured flat from 20 Hz-48 KHz, and seems unlikely to be lacking in bass control due to its <1 ohm output impedance. Again, the ABX testing would help clarify that there actually is a bass difference between the O2 and the Cmoy (which also has a low output impedance).
I would be very surprised at audible noise on the high-gain setting that was not due to the source. I have never heard any noise at any volume or gain setting attributable solely to the O2. Perhaps there's an issue with your O2, or else you are boosting the source to the point where the noise is finally audible?
Lieven you got a BIG response from nwavguy’s blog. What he said:
“Someone could set up a blind test between the O2 and an accurate amp Leiven really likes, and he would no longer be able to tell the amps apart because his brain wouldn’t know what to expect”
thing is…people can think what they want to think about a product…why all the fuss? It’s not like nwavguy is fussed about it anyways, hes just using headfonia as an example, his tone is exactly the same as how hes been writing his other writings (ie i dont think what he wrote was intended to be negative nor is it BIG). He probably wouldnt have cared, but people kept posting stuff and asking questions about it on his blog.
Agree, Video answer in youtube will be nice 🙂
I guess all the violectric amp users are fooled by placebo then.
Luckily I’ve gotten rid of that Zana Deux. I bet it would measure very bad next to the O2.
I don’t understand why people are so mad about the review. Me and L clearly acknowledged its good technicalities. I even said that the black background is unheard of on any portable amps (and that includes amps from ALO our sponsor among others). So we don’t like the mids and the bass is not impactful enough for us, is that wrong?
Seriously, read the review again before you get all defensive about the O2.
Unless you guys are expecting a perfect 10 review which is not going to happen. Read all my amplifier reviews, I never give a perfect 10 review on any amplifier even the $6,000 ones.
I believe the reason might be one or more of the following:
1. In all my time reading Headfonia reviews this is the one that I perceive as the most negative one (honestly can’t think of a worst one although probably one exists). I even remember in one review a commentor asked Mike how come most if not all the reviews on this site are so positive and Mike replied something along the lines of “I can’t help but write about the stuff I like”… Well you made it quite clear you don’t like this amp, but it is unclear why (and I don’t mean your “explained” why, I mean we are wondering if there is a another hidden why and what it might be).
2. I don’t think I have read many of your reviews rating cheaper gear higher than more expensive gear (I’ll be happy to be corrected!). In this instance the O2 is probably one of the cheapest amplifiers on this earth (bar Chinese brands) and as expected it scored a pretty lousy review. I understand that usually you get your money’s value but there should be at least some products that pounce much heavier than their price, that’s just the nature of worldwide commerce and competition.
3. This review is in contradiction to allot of other reviews out there which stress how transparent it is. How can it be transparent and lack some aspects of sound at the same time? Make no mistakes, lack of bass (or mids) is coloration! True naturality does not (should not) sound like anything at all…
Assuming you knew about the amp’s reputation before reviewing it, it looks very suspicious that your observations on it nailed exactly what some people would consider “natural” and “sterile” to supposedly mean.
4. Unlike allot of the gear you review, I actually own an O2. And my impressions are very different than yours (coupled with a pair of DT-770 it rocks my world all day, every day at work. There is absolutely no bass missing. And I listen to electronic music with lots of bass. It compares excellently with my home Asus Xonar STX + FA-011!). Now I understand that different people experience things differently but the magnitude of difference between my experience and yours, in my opinion, cannot be simply attributed to different taste/subjectivity. this has really caused me to question how much can I trust the rest of your reviews on gears that I have not heard (and might not get a chance to hear before making a purchase decision)? Can I trust them on a $500 piece of kit? what about $1000? and what about $90? you get my point.
5. Unlike allot of the other gear reviewed here, the O2 has no financial backing. I’ll leave any possible implication out of this comment, but it does raise some questions (not meaning to open any huge discussions on this, but just didn’t want to omit this).
I am not trying by any means to attack you, I am a close follower of Headfonia for over 6 months now (and have read allot of your older articles), I am just expressing my thoughts after reading the article.
I do believe that you are expressing your honest opinion, and from nwavguy’s reponse it seems he also comes from that standpoint.
BTW if you honestly encourage open discussion in the community it would be great if you could respond to his arguments and explain your point of view, although I fear for allot of people nothing short of a youtube video blind test would suffice 😉
1. Did you read his review about the nfb 12 ?
2. He did said the c421 rival more expensive amp.
3. I think the reason of people reaction coming from the old flame with nwavguy
I’ll answer one by one:
1. I have actually read the review about the nfb 12 when it was published. I had no idea that was a $200 amp! definitely a much worse review than the O2 but still relatively at the bottom of the scale of high end audio.
2. Yes he definitely likes the C421, but which actual more expensive amps is it better than?
3. I have absolutely nothing to do with the flame war (personal opinions aside) and (gasp!) even visit head-fi every now and again 🙂
BTW Lieven even says that the Fiio E10/17 have better mids than O2 which
to me is the same as saying “I like my sound colored in this specific
way”, doesn’t have much to do with the amp as an amp (at least that’s the way I see it).
I wonder how can Lieven says that the E10 have better mids than O2 when both of their frequency response are equally very flat. Even the E10 has quite a lot of more distortion compared to the O2 (altough it’s still well under audioble level).
I believe the E10 should be transparent enough and should be unable to be distinguished in a blind test. The same should go with the Sandisk Sansa Clip+, which I actually have, and cannot be distinguished in a blind test with the E10 because both are equally transparent enough. (Call me “tin ear”, if you have to)
About all of this “Subjective vs Objective”, in my opinion, it’s perfectly okay if someone like colored (“synergetic” amp) or neutral (“transparent” amp). I think I am belong to the neutral amp (more like, transparent sound reproduction) camp because I believe music should be enjoyed as how the artists & recording engineer means it, therefore adding coloration and euphonic distortion to the source will betray their expectation about how their expression should be conceived to the listeners.
But all in all, can’t we just exists alongside peacefully?
The problem with subjective reviews is that they are comments on what the reviewer likes rather than the accuracy of the sound. Not to be rude, but I don’t care what sounds best to the reviewer. His ears, brain, headphones, and tastes are different than mine.
The goal of audio reproduction should be accurate sound. The goal of audio production, in studios, should be pleasing sound. It’s not the job of my amp, headphones, speakers, preamp, CD player, etc. to change the sound that the artist, producer, and engineers created.
Asking subjectivist and objectivist audiophiles to exist “alongside peacefully” is like asking faith healers and medical doctors to get along.
Partly agree, partly disagree. We need both. The reason for knowing whether the reviewer likes the sound in any respect is not because it’s random information – it’s because the reviewer has a track record and that info can be compared to many things. It’s more difficult than “purely” objective info, but reproduced sound itself is a long way from a perfected science, even in the so-called “straight wire with gain” that none of these amps really is.
You wrote “reproduced sound itself is a long way from a perfected science, even in the so-called “straight wire with gain” that none of these amps really is.”
How better to measure whether something is a straight wire with gain than to use modern, state of the art test equipment? Claiming that you can hear things that modern audio test equipment can’t measure is like claiming your eyes have better resolution than a scanning electron microscope.
If you can’t hear the noise or distortion products that an amp adds to a signal it is, audibly, a straight wire with gain. What actually happens is that accurate products are often rated more poorly by subjectivist reviewers who prefer some type of euphonic distortion to accuracy.
“because the reviewer has a track record and that info can be compared to many things.”
Really? What is his track record and how do you compare it? Reviewers are subject to biases just like the rest of us. Secretly put an O2 into a Red Wine Corvina $1000 headphone amp’s case and then ask a subjectivist reviewer to compare that “$1000 Red Wine Corvina” to a $144 O2 in a JDS Labs case. A large majority of subjectivist reviewers will claim that one or the other is audibly superior. Nothing makes the need for ABX testing more obvious than an experiment like that one.
I’ll share a brief story to illustrate the point. I had a piece of sound processing gear in my listening room. A self-proclaimed golden ear audiophile claimed that it degraded the sound just by being in the signal path. So I switched it in and out multiple times at his direction. He was aghast that I could not hear how much better the sound was with it out. He suggested that I might not be as experienced a listener or that, maybe, I even had some form of hearing loss and should get it checked out by an audiologist. All I really was doing was muting the sound for a split second at each “switch.” The “offending” component was not even connected to the audio system — just AC power. When I revealed what I’d done, he stormed out, never to return (thank you, blind testing!).
A top-notch amp should not sound good. It should be accurate.
I’m sorry but I’m not a “subjectivist” nor a golden ear audiophile. I’m just an ordinary person whose brain and auditory system is far superior to your stone knives and bearskins.
But I do agree that a lot of the people types you mention can be more of an obstruction to fidelity than wires made of less than ideal materials.
I agree that blind testing (such as putting an O2 in an RWC case) can point out bias and placebo effect, and/or eliminate them.
The problem is when people respond to your bias example by then proclaming that a) there are no differences between amps, cables, CD players, etc. and b) measurements currently can point out all aspects of sound.
For example you state:
“How better to measure whether something is a straight wire with gain
than to use modern, state of the art test equipment? Claiming that you
can hear things that modern audio test equipment can’t measure is like
claiming your eyes have better resolution than a scanning electron
Your logic there is false.
Why? For example, spy satellites can see everything on the surface of the earth. Yet, things go unnoticed which national security people wish they had known about. How can this be? Because a human being has to determine what is significant amongst all those trillions of trillions of bytes of data.
Similarly, it is possibly true that we are currently capable of measuring any one small sound quality, but we are far from creating tests that can predict the response of audio equipment to complicated groups of sounds.
An even better example is weather.
For $99, you can measure all the relevant atmospheric data at one particular point. Meteorologists have millions of these stations everywhere, and have been spending years developing competing computer models, yet they still predict rain when it does not happen and vice versa.
You can put all the electrical test signals you like into an amplifier, and it won’t predict what will happen when you put The Beatles – Abbey Road into the input. And then when you have adjusted your design so that Abbey Road is reproduced poorly, it still might not work correctly with Skrillex – Equinox in the input.
Love hearing all the “stories” that objectivists throw out there.
Fact is, the amp is only one part of the overall system. So why put all the emphasis on the “wire with gain” when your headphones and recordings are not neutral in the first place.
One little suggestion for blind testers: Make it fair. Let the tester control the handling of the gear, but give complete control of the timing of the changes/swaps/etc. to the testee. If you think about this it will make sense.
Seems that you’re more concerned with reproducing music, rather than listening to it.
Also, the faith healer/doctor metaphor is neither appropriate or accurate.
When you say “I wonder how can Lieven says that the E10 have better mids than O2 when both of their frequency response are equally very flat.” How do you know that frequency response graphs indicate something about the midrange sound?
There are two aspects of this that are ignored by many people:
1 – How do you know that frequency response graphs indicate sound quality?
2 – How do you know when the frequency response graphs are “good enough”?
I said that?
If you read carefully I quoted directly from user DeliciousFlatFrequencyResponse’s post, that is why I surrounded it by double quotes.
That is why at the beginning of my post, Disqus put:
“To DeliciousFlatFrequencyResponse – I am replying to the post you made right above mine”
The discussions make no sense unless you read them in the context of the thread.
Lieven did not actually say that, that was a mistake I made (if you read a few posts down..).
It was Mike, and he said: “The mids are moderately thin in comparison to
amps like the C421 or the Fiio E10/E11/E17 that Lieven and me both
You completely distracted everyone from my point. So I have changed Lieven and E10 in the quote to ___ and ___ , since I am talking about the overall methodology.
But now you understand why this discussion never ends – no one notices any actual points that should cause them to question their viewpoint.
@twitter-432989079:disqus : Sorry that was not my intention! I accidentally originally wrote what I wrote in regards to Lieven, but after he pointed out he said no such thing I corrected it and apologised. Disqus actually messes up the order of yesterday’s conversation, I did not bring it up again, I only commented after Lieven (look at the time stamps and you will see what I mean).
Anyway, I completely understand what you mean, you have actually revived this conversation after a few of us (‘crazy objectivists’ as we are fondly known around these parts) have given up 😉
The point you are making is the point I originally made… or tried to make. I would love someone to take up the challenge of trying to differentiate between two flat measuring solid state amps in a double blind test… but I have a gut feeling it is never going to happen 😉
The FiiO E10 approaches audible transparency so long as the software volume control is set to MAX and you use the E10’s volume pot. This is not an ideal situation for some users.
@DeliciousFlatFrequencyResponse:disqus :I also tend to be skeptical that the E-10 can be distinguished easily from the O2. One way or another Mike and I think Lieven commented previously that the O2 is the better amp (simple economics at play). So how can Lieven now say the E10 is better in his opinion? I’m just a bit baffled.I also 100% agree with you in regards to coloration being ok and in fact all my kits are un-ashamedly colored. However the color is in the Headphones, not the source/amp.My gear: FA-011, DT-770, Shure DJ750 and more- none of them remotely natural.However sources/amps: Asus STX, Sansa Clip+, O2 – all of them strive to be transparent.I understand people have different opinions, preferences and views however this review feels like it’s more than that.”can’t we just exists alongside peacefully?”
I sure hope so! After all we all share a hobby/passion!
I’m not commenting on this thread in general but if you had read my part or the review more closely you would have seen I never made such a statement, I didn’t even mention the E10 as a matter of fact and I only spoke of the Violectric, so I have no idea where you’re getting this from. You can discuss all you want but please don’t go stating stuff mentioning my name if I never said it. It makes me wonder what else visitors misunderstood/didn’t read.
My Apologies Lieven!
The sentence I was referring to is: “The mids are moderately thin in comparison to amps like the C421 or the Fiio E10/E11/E17 that Lieven and me both liked”
This is under Mike’s impressions, I somehow thought I saw this on your part but was obviously confused (maybe because of the mention of your name in that sentence).
Anyway I apologise again, it was not my intention to create false information.
PS What do you mean by not commenting on this thread? why?
Well a last one then. I think Mike’s comment pretty much expressed my feelings too. That being said. 1. I can accept people preferring mesurements, but a lot of the “objective” guys seem to be unable to accept our point of view. I find that sad. 2. We even say the amp is great (but we don’t enjoy it because of the way we think the bass and mids are) yet we get critisized for not giving it a full 10/10 or for not following the ideology that it is the perfect amp. That’s it, I’ll get out of your way again now. Apology accepted btw 😉
Measurements definitely have their place and are helpful as a guide, but they are not to meant to be followed so blindly.
In the end, one needs to try equipment out for themselves to see if it’s what they are really looking for. Nothing replaces first hand experience.
The criticism is not due to you not giving a 10/10 score, it is not about objective vs. subjective and it is definitely not the preference of measurements over subjective impressions (nwavguy himself posts subjective impressions with his reviews). It is also not about not having measurements or any of that – we do not expect that of you. Allot such things got thrown here or responded to ‘objectivists’ posts without any connection with what people were actually saying.
It is very simple: nwavguy claims the amp is transparent. You say according to your listening it is not. There is proof that expectation bias could very well change the way stuff sound to you.
It all come down to this: you *should* do a blind test against another transparent amp (preferably one that you like such as the v200) and verify that you can still hear those differences, even when you don’t know what you listen to.
If you choose not to do so that is of course OK, but know that your impressions are not reliable because you have not refuted the existence of bias.
I am not expecting a response as it is obvious you and Mike decided it is better to opt out of the discussion, however you seem interested to know what the problem is, and it seems you still don’t get it so I am trying to explain it as clearly as I can.
I think most people aren’t mad, but they felt this article doesn’t do a whole justice to O2, especially on the fourth part of the article which sounded like you had a problem with the ideology behind the amp(!) instead of the amp itself.
It’s OK to critique the amp, but not the ideology behind it, as it ticks people off fast.
Not only the criticism falls on deaf ears, it stimulated people into negative thinking.
At that point basically you turned the whole thing into a subjectivist sermon.
And now you wonder why people are posting their rebuttals.
By the way, I respected Nelson Pass as much as I respected Bob Carver.
I disagree. Mike’s point in the fourth part of this review is measurements alone do not necessarily guarantee a optimal sounding amp. It’s a different view point as many in the industry do not share NwAvguy’s philosophy.
The bigger point is Mike and Lieven have a different philosophy(as stated in the article) on reviewing gear than NwAvguy. There’s nothing wrong with having a diferent viewpoint. And I think it’s a bit unfair to be critical of a subjective viewpoint on the O2, its simply the way Mike has every reviewed every piece of gear on the site.
measurements can guarantee that an amp is audibly transparent an therefore its sound indistinguishable from any other transparent amp.
if the “view” you talk about is that not all amp that measure well (no coloration) sound the same, a DBT should show that, such view would also imply some sort of unknown electro-acoustic effect to account for the differences in sound. If the view is that accurate gear sounds bad or is not “musical” enough then all accurate gear should sound bad and get similar bad reviews.
I think you completely missed my point.
The problem is being a subjective (or objective) review doesn’t give the reviewer(s) a free pass to poke the standpoint of the product designer or lack there of.
Keywords: a pair of good ears, good/bad sonics, strong belief, wrote so convincingly
It is akin like suggesting an atheist to believe in the existence of God.
I could be missing something, but I still see no explanation in that link for NOT using ABX testing. No measurements required…ABX is just a way to validate that one is hearing a difference between two sources. If there truly is a difference, it should be easy to tell (i.e. you should get near 100% on the ABX trial). It should actually reveal more subtle differences than can be detected another way, since auditory memory deteriorates after only 0.2 seconds, and it’s basically impossible to switch cables that quickly.
Sounds like you didn’t read the link thoroughly. Please reread.
Their philosophy is clearly defined.
I read it “thoroughly” and am a published author as well as being an electrical engineer in the aerospace industry. Paul Leskinen is correct. If you interpreted it differently, you are wrong. There is nothing presented in that article that argues against ABX testing.
In fact, there is no valid argument against ABX testing, period. Arguing against it is as foolish as arguing against double-blind testing in the pharmaceutical industry. Stop rejecting science in favor of mysticism.
Glad to hear that you’re an engineer. I stayed at a Holiday Inn Express last night.
Regarding ABX testing…please refrain from putting words in my mouth. You’re drawing the wrong conclusions.
Headfonia doesn’t do ABX. Period. End of story.
If you don’t agree with this review, use your publishing skills and write your own O2 review.
Engineer nothing. I went to Yardale where I had a 4.0 GPA!
As I said in a previous comment, I have an O2, and I like it a lot because I think it sounds clean and transparent. All Mike has said is that its a good, clean and transparent amp, but he didn’t like some of the pairings he listened to. Frankly the tone of some of these replies are a little disrespectful or juvenile.
I’m really not sure what people are calling for when they are calling for a blind test. You are asking him to compare the O2 in a blind test against another ‘audibly transparent’ amp because you believe he is making up the differences between the different amps he reviewed the O2 against? Who in these replies making the demand for a ABX test, actually has the equipment or understanding to verify whether the amps he was comparing against are actually ‘audibly transparent’? Who here can nominate an amp that is measured to be ‘audibly transparent’, and not just based on the manufacturers published specification? Has anyone here, with the proper equipment, actually even independently verified if Nwavguy’s design actually meets the published measurements and is indeed ‘audibly transparent’?
Nwavguy has called out people and manufacturers using blind faith and sighted listening to arrive at their conclusions and yet there are people here who are defending the O2 with the same unshakeable beliefs. Mike is allowed not to enjoy the sound of the O2, just as he expresses his opinion on other gear in any number of helpful reviews he has written here. If you feel that there is some error in his methodology, and you have the equipment to demonstrate there is no actual difference between Product A and Product B, then I suggest you post up your measurements and findings instead of calling for these ‘challenges’ from the sidelines. Otherwise, stop waving around an ABX test like a baseball bat.
Your belief that the O2 is measurably superior and therefore subjectively superior is as much ideology as anything else. As I said, I like my O2, but I don’t pretend that my subjective presence isn’t based on anything other than my brain telling me Nwavguy sounds like he knows what he is talking about, and my ears telling me I like what I’m hearing.
“Your belief that the O2 is measurably superior and therefore subjectively superior is as much ideology as anything else.”
I don’t think anyone has stated that (the part about measurably superior->subjectively superior).
The complaints are more about attributing coloration (lack of bass punch and “wrong” mids) to an amp that isn’t supposed to have coloration at all. Blind testing would be useful because it could confirm or disprove that the amp is in fact audibly
This is my issue. Which amp is he supposed to compare it to that is supposedly audibly transparent, so that he can do an ABX test to it? No one, except nwavguy and the manufacturers, have the equipment to actually prove that any of these amps are audibly transparent. As nwavguy has pointed out, most manufacturers provide insufficient or inaccurate measurements for their products. There is no credible, independent verification from anyone else that the O2 actually measures as well as it does. Under these circumstances, what ABX test can be performed to demonstrate that the amp is in fact ‘audibly transparent’? Yet there is an assumption that the O2 is in fact audibly transparent. That is an act of faith as much as anything else, because all you are doing is taking the designer’s word that the amp he has designed is better and superior. nwavguy has been more transparent about it, but in the end it is the same as any other manufacturer publishing specifications.
It’s reasonable to think that Mike could ABX test against another amp that he likes with the HD650, and see if under blind testing his preference changes. Even if it does or doesn’t change, all ABX testing tells us is that Mike prefers the sound of one or the other. It can’t tell us whether or not the O2 is actually neutral and uncoloured; it just tells us about Mike’s preferences in terms of sound and whether his impressions were coloured by everything else he knew about the O2 and its design. In the end, without a universal reference point the ABX testing process – which sounds like a very objective and scientific – is just going to return subjective information about what Mike prefers. In which case, does that really differ from the review as it stands – Mike’s subjective opinion on which amp he prefers?
If you are asking for Mike to do an ABX test, in essence you are hoping or expecting that his opinion of the O2 might change – and this is a bias as much as any other hope or expectation. This review was conducted in the same way as every other review on this site. It speaks volumes about the subjective faith that Nwavguy has inspired from his objective design if this is the only review that was ever so scrutinised in the name of ‘objectivity’ because people are unhappy with the outcome. If you don’t want want Mike’s subjective opinion, then my suggestion is: don’t read his reviews.
Let me repeat, I have an O2, and I like the sound. I like Mike’s reviews, and they are enjoyable to read. I’m not going to demand he change his way of reviewing things if he doesn’t like something that I do.
That’s a lot of text and questions for a very simple answer: double-blind test.
Like NwAvGuy suggested in his latest article, you should read it. Should also answer your other questions.
You don’t seem to understand what transparency means.
Mike would actually have trouble identifying which amp is which (O2 vs. V200 for example) in a blind test.
Please do not suggest I have not already read the article, and I have not understood it. I’d like you to actually read my comments and understand them. Since you feel that I have too much text, I’ll ask these two questions:
1. Has anyone independently verified in a credible fashion that the O2’s published measurements are accurate?
2. Has anyone independently verified in credible fashion that the V200, or any amp’s, measurements are accurate?
I accept the idea that good measurement results should result in a amp that sounds transparent. What I am casting doubt on is that everyone has taken it as a given that the O2 meets its published measurements, and therefore they attack the review on the basis that the O2 is absolutely guaranteed to be transparent because Nwavguy’s measurements say so. You are taking him at his word, when Nwavguy has called BS on other manufacturers either providing false or inaccurate measurements without any verification. You are sanctimoniously declaring the review as deeply flawed because the O2 is definitely, 100% for sure, proven to be measurably transparent, without any basis to go on besides the statements of the designer!
I am not saying that blind testing may not uncover that there is a difference or no difference in sound between the O2 and another amp. But “transparency” is as much of a relative buzzword as “coloration.” Without knowing if the O2 is actually measurably transparent, all a blind test will show is that Mike and L. were hearing differences that either were there or weren’t.
1. Under a blind test, the O2 sounds the same as another amp.
2. Under a blind test, the O2 sounds different.
At no point does the result of this test actually tell us whether or not the O2 is ‘audibly transparent’. It just tells us how the O2 sounds compared to another amp, and none of these amps are amps we know for sure have truthful or complete published measurements. And yet people are insisting that blind testing will demonstrate the O2 is transparent.
“I can’t hear the difference between X and Y” is only relative transparency.
“I can’t hear the difference between X and Y and both X and Y have been shown to be measurably accurate.” is absolute transparency.
People are making the case that the O2 is absolutely transparent, when all the blind test will show is that the O2 sounds very similar to another amp. This is my problem with people calling for a blind test as if it somehow proves something empirical about the O2.
I don’t think I am being unreasonable in having a degree of skepticism about how critical this amp’s defenders are being. I like the O2, I think the designer knows what he is doing, but I am not going to go making leaps of faith on that basis.
@La-chan: I don’t know if “anyone independently verified in a credible fashion that the O2’s publish measurements are accurate” but I have made some measurements myself and I see nothing wrong if I compare them to NwAvGuy’s measurements. I don’t have access to an expensive audio analyzer but a couple of very well measuring A/Ds and D/As that can be used to measure the flat frequency response, low THD, IMD, crosstalk .. both with dummy and headphone loads. (Unloaded measurements are useless. see mini3, c421 …)
Yes, I am taking him at his word that other manufacturers have produced bad equipment because nobody has shown otherwise. Even though RMAA is quite limited you can easily measure some of the flaws NwAvGuy has published. Take a look at the threads on some audio forums that discuss his articles. Nobody wrote: “hey look at this, I measured something completely different.”
I am declaring this review is flawed because it makes claims that contradict both measurements and several other reviews spread over different audio forums.
> 1. Under a blind test, the O2 sounds the same as another amp.
vs. a V200? This would be enough to show that the reviewers approach is flawed.
Also, you don’t need both X and Y to be measurably accurate in order to show “absolute” transparency.
> And yet people are insisting that blind testing will demonstrate the O2 is transparent.
How high do you think are the chances that two different amps sound identical without them being transparent, i.e. both have identical coloration/flaws? Very, very low I’d say. Of course, a single test wouldn’t prove anything and nor would 100 tests be 100% proof that it is transparent..
The bottom line: It is pretty well proven that measurements reliably predict transparency in an amplifier, via double-blind listening tests. If there is an audible difference, there is certainly a measurement that will show it using current technology. There is nothing “magical” about our ears–they are easily fooled. If Lievan and Mike claim that the O2 is not transparent (e.g. thin bass and midrange), I will stand up and call BS to their faces, as they are clearly biased, and refuse to even acknowledge that blind testing is a valid tool. If they want to purvey their biased, sighted listening tests to their gullible fanboys, that’s fine–buyer beware. I for one, am completely done with Headfonia, as it has absolutely lost all credibility in my mind. Face the facts: A sufficiently well-designed amplifier will sound EXACTLY like any other sufficiently well-designed amplifier: Any amplifier with sufficiently low output impedance, sufficiently low distortion and flat frequency response is “transparent.” End of story. All of your flowery adjectives used to describe multi-thousand dollar amplifiers prove NOTHING. You ARE subject to bias (regardless of your denials to the contrary), and that is a fact proven by multiple studies. If all of the rest of you who want to spend thousands on their “preferred” esoteric tube amplifiers that color the sound in a pretty way, well, there’s a sucker born every minute.
Bye bye, Headfonia.
Yep that pretty much sums it up.
Not to mention the fact that they have contradicted themselves; in the past they have expressed that it is a great amp (both on Facebook and in their comment section) well deserving it’s high praise but now somehow the opinion has changed with no given explanation.
“…If there is an audible difference, there is certainly a measurement that will show it using current technology…”
Sorry you were not able to convince Mike and L to change the review style of their website. Their philosophy has already been clearly stated several times. If you are not happy with the direction of their review style, there are many other measurement based review websites out there. A few posters are determined to discredit their review style and the direction of their website and I’m still not sure why that is. Different strokes for different folks. Why all the fuss?
Many of us are happy to see a site like this where reviewers use the tools that they were born with…their ears.
> Many of us are happy to see a site like this where reviewers use the tools that they were born with…their ears.
Ever heard of BIAS? Ah.. never mind.
And the other shoe drops….
Guess you’ll be leaving too?
One of the primary rules of film criticism (and this applies to all forms of criticism) is to know your bias. EVERYBODY has bias. Maybe it is favoring measurements over all else. It could be putting a lot of weight on how something looks. Perhaps you have a bias towards a certain sound, like MR JDSlabs who admitted to being a bass boost guy. I enjoy reading the reviews here. I come hear looking for their opinions. Mike and L are good about stating what sounds they like or why they like or don’t like something. If you don’t like the way they review, read elsewhere.
Yes, they listen. That’s fine. How do they remove bias from their sighted listening tests? Why do they not employ an ABX box for that purpose?
Maybe you have an ABX box that they can borrow?
No, I do not. But then, I don’t have a blog that reviews and compares headphone amplifiers—my point is that THEY should have an ABX box, or at least attempt some kind of blind test when comparing amps.
Oh, it just sounded like you had one from all of your comments.
Have you ever ABX tested your own system? Just curious.
If you say that you have done ABX testing and could not differentiate between products X and Y, then the subjectivists will immediately pounce, claiming that it’s proof that ABX testing is flawed, that you lack listening skills, that the rest of your system is somehow lacking, etc.
It’s a no-win scenario — I know because I’ve been on the losing side. Most of the subjectivists who prod you to perform the ABX testing that you advocate will never agree to participate in such a test themselves. They will posit that product X is audibly superior to product Y — they “hear” the difference, so it’s real, not bias or imagination, and is not open to discussion. In essence, any test that fails to support their beliefs is at fault; their beliefs are not open to question.
So who is doing the listening training? Challenging what someone hears is problematic unless you are well trained in listening yourself. It seems like you could miss all kinds of things by being tuned in to certain sounds more than others. Are there people so good at this that they are sure they have all the bases covered? My take on the reviews is that reviewers have to operate within a certain range of listening skills in order to not wander all over the place and get lost. But when critics weigh in with very different opinions, I wonder if they have a wider range of skills, a narrower range, or they just learned a different way completely? Since there does not seem to be a universal guide to learning critical listening.
In my opinion the problem is those inexperienced people who thought that the O2 is more than what they paid for. The second part is important as it actually applies in all aspects of our life.
It’s amusing isn’t it? For something that has an “Objective” moniker in its name, the people who defend it sure don’t strike me as having that characteristic to me!
In my opinion your comment is insulting a lot of people you don’t even know and should be removed including your right to post.
I see that I had touched a nerve.
Look, I will say this again as it is obvious that my intent was lost. You are getting a battery-powered op-amp driver with the O2 and that is EXACTLY what you are going to get performance-wise. The O2 is not going to somehow magically outperform a Zana Deux, a β22 or a GS-X. It’s just not going to happen.
That’s as silly as me buying a Honda Civic and expect it to outperform say, a Mercedez-Benz C200 Kompressor.
“You are getting a battery-powered op-amp driver with the O2”
So I understand that you claim to be well versed in audio design? maybe you can try and design a better amp.
Regardless there is proof on the internet that the O2 is transperant, no amount of mambo jambo you write here (“magically outperform” as if there is need for magic for this to happen) is going to change that, if you think it is not transparent, i.e. discernable from other “amazing” (transparent) amps with impresseive names etc. prove it by distinguishing between them in a blind test.
As long as you do not do so your words are air.
LOL you cracked me up so bad my sides hurt!
“You are getting a battery-powered op-amp driver with the O2”
You couldn’t possibly have written this with a straight face. First off, battery power is the quietest source. Why do you think Naim (well regarded audiophile product manufacturer), among others, makes/made battery-based gear? Isn’t highly-touted AMB Mini3 battery-based with op-amps? Even Violectric (Liked by Mike & Lieven) uses op-amps. Your point is meaningless. Have you no understanding of the whole music production chain? How many op-amps, whether battery or AC powered do you think all your music went through? Hundreds, if not thousand(s), many different types and makes.
The O2 doesn’t need “magic” to beat many other more expensive amps. Here, straight from AMB’s web page (Re: ß22)… “The all-discrete (no integrated circuits), fully complementary and cascoded topology, high-current MOSFET output stage, full class A operation and carefully tuned operating points vanishingly low distortion (emphasis mine), high speed, wide bandwidth, low output impedance, and high output power. All elements of the design were critically examined to create an amplifier that performs as well on the test bench as it does with music.” So, a much less expensive “battery-based op-amp driver” beat the ß22. Google for yourself.
It’s like seeing another form of battle between fanboys. Mac vs PC, Android vs iOS, and now this.
Macs are clearly better.
Your comparison is completely invalid as the headphones you speak of have different presentations (and these are ok to be subjectively preferred).
The amp in question was built to be transparent. If this was done successfully then it is impossible for it to be thin and lacking bass etc. and there shouldn’t be any subjective preference to it over other transparent amps.
If not transparent then this would be of interest but that does not seem to be the point the review is trying to make.
It might sound like a bit of a wimpy cop-out, but I genuinely don’t see why us audio enthusiasts need to be strictly divided into to warring camps – subjectivists and objectivists. I for one enjoyed the review as always – I enjoy reading Mike and L’s comments and I also like to see the measurements too if possible, is that wrong?
The way I see it, Headfonia isn’t anti-measurements at all. The difference between this site and NwAvGuy’s blog is simply that here the measurements are done by ear. Like a reading an opinion of an artist’s album then you just have to be aware that the reviewers have their own taste in and experience of music, and to realise your own perceptions of the same kit may well be different. I don’t get the feeling that this site negatively reviews cheap gear for the sake of their sponsers, some good examples to the contrary are the PA2V2, JDSLabs Cmoy, Fiio E10.
Purely for your own interest (or perhaps also for charity), rather than to appease the rabid objectivists, I think it would be great for you guys to do some kind of experiment comparing the O2 with a more expensive amp that also has low output impedence. I think but I’m not certain that the Violectric qualifies, and it would be fun to use some LCD-2s or HD650s for the test. I personally think that measurements can tell you everything, so long as some of those measurements are done with your ears!
>The difference between this site and NwAvGuy’s blog is simply that here the measurements are done by ear.
There are at least two things wrong with this:
1) NwAvGuy (and others) also did comparisons by ear with the DAC1 for example.
2) Are you sure that here the “measurements” are done solely by ear? (see the “What We Hear” article).
Why is it wrong to have a subjectively based headphone review site? If I wanted only measurements, I’d go to Nwavguy’s site.
Seems pointless to try to change the direction or discredit this website. Mike and L are doing a great job and many appreciate it.
May I ask which recordings have you used for reviewing the amp? One may naively think that a neutral amp is more suitable for reproducing some genres (classical, acoustic jazz) than some other ones (rock, electronic). Could this wild guess be correct, at least to certain extent?
Don Vittorio Sierra
NwAVGuy is quite powerful. Think about it guys, everyone is arguing about a sub $200 amp because of his strong views LOL. I say buy an O2 for yourselves if you really want to know if its good for you or not instead of joining the o2 argument wars before listening hehehe.
I for one am intrigued by the infamous o2 but I can hear the differences in the sound between products that are typically called snake oil like different power cords or even reversed interconnects so I myself really want to listen for myself if the o2 really makes the music flow without coloration.
have you tried listening to those differences without knowing which component are you listening?
Don Vittorio Sierra
Like I said, I’m not joining the argument yet since I haven’t bought the o2 yet
I meant the differences between power cords, interconnects, etc.
Don Vittorio Sierra
Oh yes I have actually pinpointed which wires were which in a blind test in fact I have pinpointed if a certain interconnect was reversed or not. I get confused though if one channel is reversed and the other is not because the overall sound with the weird left to right difference throws me off.
Don Vittorio Sierra
It makes me want to buy an o2 just to see what all the fuss is about
It is pretty good for what it is but it ain’t replacing my β22 anytime soon.
Don Vittorio Sierra
It’s amazing how many of you seemed to be surprised that Mike & Lieven did a subjective review of O2 without measurements, blind tests, using the scientific method, setting a hypothesis first, laboratory equipment, PHDs in physics and mathematics, and Data from ST(Star Trek):TNG. Instead, electing to use only their*gasp* ears?! Shocking! It’s only the way they’ve reviewed every other piece of gear on the site.
Seriously, where was all the howling and crying when Mike gave a lukewarm review of the very neutral(and rather expensive) Meier Concerto and StageDAC? If one had been following Mike site at all, he stated quite a few times that many audiophiles(you know the people who like to enjoy music) and himself included prefer warmer sounding gear. That is a major reason(among others) why tube amps have maintained their popularity. Knowing that, is it surprising that Mike & Lieven were not completely enamored with the O2?
That is not to say, neutral sounding gear isn’t good. Far from it, as many(audiophiles included) prefer neutral sounding gear. I apologize for my comment’s tone, as I rather not be involved in any arguments or flame wars. What irks me is the “my way or the highway” approach of some of you. Not every person prescribes the NwAvguy’s philosophy nor should they. In this audio hobby of ours there are quite a few ways for one to reach audio nirvana. That’s the good thing about it, there’s something for everyone(and every budget).
That is because the gear in question is the holiness O2 borne out of love and sacrifice from someone whose first move to promote his philosophy is to attack and slander established DIY designers in various internet forums.
If anything, the O2 is a perfect testimony on how devastating FUD marketing can be if executed properly.
I love how the Mini3 review is apparently “slander.” As NwAvGuy himself put it, various people still seem to be convinced that he tested a Mini3 built out of parts from a toaster oven, and the measurements were all sabotaged, and that if AMB somehow “got lucky” with the measurements (?) that they should be allowed to stand, that AMB is experienced and NwAvGuy could not possible appreciate the physics-defying unmeasurable magic subtleties of three channel design…
It is best not to attack someone for slander by slandering them.
I do not think the NuForce µDAC-2 nor the Schiit Asgard qualify as “established DIY designers”. Those are commercial companies with no excuse for the product errors they made. As for AMB, their product(s) may be DIY or purchased whole. There was no slander or attack. Those products were simply shown to be either dangerous to headphones (Asgard) or not meeting posted specifications.
If you purchase something, don’t you expect it to perform to the manufacturers specs? What if your new AMG 591hp V-8 roadster only reached 115hp and 55ft-lbs torque? Would you not be outraged? If the manufacturer said “Well, our test battery must have been overcharged and we got lucky but we measured what we posted” would you not be disgruntled?
In the expose of the various products, where they did have some good points or performance, it was stated. This is not slander. Look up the definition before throwing words around. Also, your comment on FUD (Fear, Uncertainty and Doubt) is not correct either. Since the specifications of the O2 are very detailed, there is no FUD as any consumer can be assured of the quality. FUD enters in when you cannot rely on your manufacturer to be honest in their stated specs.
> use only their*gasp* ears?!
Ever heard of bias? Guess not.
@Brian: Why all the hate? Do you feel threatened by the O2 because it performs better than the b22 in terms of distortion as measured independently on H-F? Or because your b22 was probably 10x – 20x as expensive? *giggles*
Let’s get this straight. I honestly think that the O2 by itself is a great product, given what it is. I find it to be an improvement compared to a vanilla CMOY as pictured in my profile image.
It’s just a shame that its some of its proponents tend to be on the… narrow-minded side, suffice to say. Just look at how your lot came here to bash Mike’s review just because it’s slightly less than stellar. Heck, if you actually take your time to read the review it actually offers a pretty balanced viewpoint compared to the usual 6moon “everything sounds good” prose so the vitriol is frankly unreasonable.
Additionally I find the designer’s move to discredit other more established DIY designers (using measurements on an improperly-built unit should I add) before shamelessly promoting his own design screams of an utter lack of class and ethics.
And regarding the β22, I don’t see the need to flaunt it everywhere. After all, great designs establish themselves by the virtue of merits alone without the need of a select bunch of people to artificially inflate its reputation in the Internet.
And that’s that. Thanks for the space Mike and Headfonia, I haven’t had this much fun commenting on your reviews. :p
Talking about narrow-minded, you assume that NwAvGuy’s mini3 was somehow broken but for example Shike measured a professionally built Mini3 with a dummy load (a simple resistor) and got results very close to NwAvGuy’s.
Maybe his way of publishing those results were not the right way, but this doesn’t change that some (?) designs of that “established DIY designer” are average at best. What I find borderline fraudulent are the claims and “specifications” on the mini3 page, but I guess you gotta be less narrow-minded to see that.
You see, you’re not the only one who can write condescending comments and enjoy oneself.
Honestly I applaud your perseverance, my reaction when I saw his comment was to roll my eyes and get on with my life… When the narrow mindness claims come out you know it’s time to gather your stuff and move to another town.
And PS Brian we didn’t “come here”, we were always here, (presumably) just like you.
All you guys should get a room and make up 😉
L: you are LIKING this aren’t you?
Not really actually. I’ve just had it with all the negative, attacking comments. No product should have this effect. We all love audio in our own way, just accept that and go read our newest review 😉
How does posting a new review change anything?
Dude. Really?! Jeez, I’m out.
Exactly what I thought. Thanks for confirmation.
Way to go pissing off L.
Gotta say that you’re crossing the line now. Your comments and attitude are no longer moving the O2 conversation forward. You’re clearly just trying to provoke a reaction as a last ditch effort to “win” this conversation. Very uncalled for.
Everyone has an opinion and it should be respected, whether you agree or not. I’m all for a spirited debate, but let’s keep it focused on the topic.
I know, I’ve picked up on Brian Fu’s “style” of commenting. I’m not trying to win anything here, just replying with stupid comments to other stupid comments.
I’m not sure what to feel because you need to pose as two different users to reply to my comments. 😉
I must agree with Brian Here… I believe he does discredit other well established designers on a constant basis and I think that is pretty much just bollocks.
You’re free to think or believe in whatever you like but that doesn’t change NwAvGuy’s and other’s measurements or the performance of said designers’ creations.
Yes, thank goodness all the O2 supporters are here to save us from ourselves.
When subjectivist tripe results in sales of inferior products and lost sales of superior ones, it harms the entire industry. J. Gordon Holt, founder of Stereophile magazine summed it up this way in a 2007 interview:
“Audio actually used to have a goal: perfect reproduction of the sound of real music performed in a real space. That was found difficult to achieve, and it was abandoned when most music lovers, who almost never heard anything except amplified music anyway, forgot what “the real thing” had sounded like. Today, “good” sound is whatever one likes.
Since the only measure of sound quality is that the listener likes it, that has pretty well put an end to audio advancement, because different people rarely agree about sound quality. Abandoning the acoustical-instrument standard, and the mindless acceptance of voodoo science, were not parts of my original vision.
Audio as a hobby is dying, largely by its own hand. As far as the real world is concerned, high-end audio lost its credibility during the 1980s, when it flatly refused to submit to the kind of basic honesty controls (double-blind testing, for example) that had legitimized every other serious scientific endeavor since Pascal. [This refusal] is a source of endless derisive amusement among rational people and of perpetual embarrassment for me, because I am associated by so many people with the mess my disciples made of spreading my gospel. For the record: I never, ever claimed that measurements don’t matter. What I said (and very often, at that) was, they don’t always tell the whole story. Not quite the same thing.”
What’s amusing about this is that Holt very vociferously opposed testers at Stereo Review and other respected publications because they refused to value listening above measurements. I subscribed to Stereophile starting in 1973.
No one can save you from yourself but you. All that has been done, in essence, is to shed some light in the hobbyist headphone arena. Not his (NwAvGuy) fault that so many seemingly good products are either dangerous to use (non UL/CE compliant), dangerous to headphones (Asgard) or don’t meet the manufacturers stated specifications (NuForce & AMB). Those are all the responsibilities of the manufacturer. Why as a consumer who works hard for your money would you buy subpar goods?
There are other good products out there. No one ever said the O2 was the end-all be-all. It was designed to be audibly transparent with low part count, not very expensive and DIY friendly with no critical tolerance parts. It has met all those points and then some. An amp is either transparent or it isn’t and the O2 meets all the requirements for audible transparency.
Other amps may look nicer, be gold plated, have 10mm thick front plates, a Blue Velvet pot, huge knob but cannot be more transparent than transparent.
That I can either build an O2 for around $50 or buy one for $150 is a tremendous value.
I often come to this website just to find out how the character of an amp or headphones … before I buy or try it..
because I have been following Mike review in headfonia until now.. I quite know how is the sound that he prefered.. what he likes or what’s not
so if there is a new stuff that they reviewed here, I immediately understood how is the sound of the new things compared to the stuff that they have tried before (and among those things there must be one-or-two that I’ve tried it too) so it’s so much easier to get the sound-image of the new things even before I try it myself.
that alone is enough to make me a reader of headfonia….
Don Vittorio Sierra
I also follow your style of reading reviews. Its the relative comparison of things and knowing what the reviewer likes that can make one learn about what something sounds like without having to hear it for ones self.
You know one of the big deal breakers with the O2 is that it’s really not friendly to live with at all.
It’s designer advertises it as a “portable amp”, but it’s far too big to put in your pocket. So count on always needing a bag with you. You will also need to stock up on 9V batteries as you’ll only get 8 hrs out of each set of batteries. Ouch, that gets expensive. Sure you can use rechargeable batteries, but the O2 doesn’t have smart charging so you need to baby sit it every time you recharge it so you don’t fry the batteries or the O2. Oh, and don’t forget that there’s no low battery light either, so it could go dead at any minute. You could skip the batteries altogether and use a wall wart charger, but then there’s yet another thing you need to drag along.
It really needs to have a lithium battery with a reasonable battery life, USB charging, and much smaller packaging.
or you know, get two sets of batteries and a wall charger.
True, but the O2 is clunky enough to lug around. Now you’ve added extra batteries, a charger, and have increased cost. Plus, you’re stuck doing the battery shuffle, which gets old quick.
Once you’ve had a true slim line amp with the convenience of USB charging, you’ll never go back.
Ely Maranhao Filho
Have you read the links?
Yes, but I’d rather hear what you have to say first hand.
Ely Maranhao Filho
Recently I’ve decided to listen music seriously again. I’ve read a lot stuff, and in the last months I acquired a senn hd650, an ath-m50, a fiio e9+e17, an audinst amp-hp and a burson ha160ds.
The diference between the headphones are obvious, but the diferences between the headphone amps, I simply don´t know… Sometimes I think the burson is better, but maybe I don´t want to admit that my money wasn´t spent wisely.
I´ll ask some friends to make a blind test, but it will take some time.
You have to call it like you see it, or should I say, “hear it”. I applaud you for telling it like it is. We all hear differently due to different ear shapes and middle/inner ear health/age, and our brains interpret what we hear differently. And then there are personal preferences, some like things spicy and some like things sweet.
True, measurements are nice, but they need to be only a part of the equation. We can’t say that all amps that measure good sound good, and we can’t say that all amps that measure poorly sound bad. The eXStatA electrostatic amp is reported to have some of the highest distortion levels in an audio amplifier, and yet while it sounds strained and grainy with the Stax SR-007 it can sound lovely with the Stax SR-009. The uDAC-2 can have high levels of distortion measured with recordings hitting -0 dbfs, but with well-done masterings the device outperforms most other gear in it’s price range.
And sometimes the electrical circuit will have a synergy with one set of headphones but not another. I don’t believe anyone can say that there is only one output impedance or dampening factor that works well with all headphones, and voltage swing or current output can greatly affect the sound as well. To have NwAvGuy imply in his blog that your review is biased, because you didn’t like it with certain phones like the hard to drive HD650, is to ignore synergy and to deny an understanding that what sounds good to one person may not to another.
In my case, I have only heard a couple of amps that drove the HD650 well enough to make me enjoy them, including the Balancing Act, Zana Deux, and Schitt Valhalla. I disliked them on my maxed Woo WA6, Dark Voice 336i, and EF1 amps – they sounded dull and lifeless and veiled when underpowered and I got rid of them. I’ve owned them twice, and came to the same conclusion. I always gravitated toward the HD600 instead, which are slightly less demanding on an amp and behave a little better with lesser amps.
No one has stated that “all amps that measure good sound good”. What we can say is that all amps that measure good (to be audibly transparent) will have higher fidelity that amps that measure poorly, and that all amps that measure good will have indistinguishable sound.
I’m not sure about the “indistinguishable sound” part though. Technically it’s a correct statement. But because different amps are made of different types of parts, sometimes sonic results are just a bit different. Maybe “virtually indistinguishable sound” is more proper.
Indistinguishable in the sense that the sonic differences that you speak of are beyond the threshold of human perception. After this threshold 2 amps might have different parts, and even measure differently, but they will sound the same.
How could 2 amps with sonic diferences beyond the threshold of human perception “not necessarily” sound the same?
“We all hear differently due to different ear shapes and middle/inner ear health/age, and our brains interpret what we hear differently. And then there are personal preferences, some like things spicy and some like things sweet”
I’ve always believed in High Fidelity and never thought of it as a religion, although there certainly is a lot of black magic in the better designs. The “hear differently” thing makes sense when we speak of absolutes like “how does it sound?”. But it doesn’t make as much sense when we speak of comparisons like “which one sounds airier?” If person A thinks amp A sounds airier than amp B, and person B thinks the opposite, then I don’t attribute that to hearing – I think there are probably other factors that didn’t get accounted for in the test.
Well, I’m enjoying the O2 with my DT48A, at first I felt the Meier Arietta was on par, but it seems that the O2 is not as limited in the frequency range span. I have also tried them with my DT48S Nagra and you can only imagine what i hear. Very Hi End sound. Simply amazing….have been posting less and enjoying the music more since i got the O2.btw the Meier Arietta was preferred over many other amps for its neutral sound, other amps like the Burson and WA6SE had slight colorations. YMMV.
How do people think this compares to the Matrix M-Stage? Any help would be appreciated.
Don Vittorio Sierra
I have a question. I don’t know if it has already been answered here but is there going to be a fixed version of the o2 where it could take higher input voltages than it can because the jdslabs O2 that I have in front of me clips with a lot of modern recordings at high gain even when the amp volume is not turned up very loud. I really love the sound of this amp even at high gain when playing non-remastered 80s cds for example using my beyerdynamic dt250-250 but once the albums are really mastered too hot, the amp starts to clip.
I can also tell that it is really an input problem because if i turn down the volume levels from within foobar and turn up the knob of the amp, the clipping goes away.
I’m finding that when the O2 drives something well on low gain then it sounds good. On high gain I seem to get a disproportionate amount of noise and distortion for the amount of gain I’m getting. For an amp that cost me $140 USD assembled (by JDS Labs), it’s a good deal I think.
Don Vittorio Sierra
I agree. I use low gain most of the time. The only time I need to switch to high gain is when the music playing is very quiet like in old cd masterings of the 80s for example. In that situation, the input clipping doesn’t happen anyways so its all good. I just want to say the O2 is a really nice amp!
Chow Chi Eng
came across this humorous analogy from my friends as I tried to give my 2 cents on forum regarding amps.
“Stop ‘educating’ people to look at audio gears in your ‘objective’ way,then conning beginners to look at those measurements every time they want to judge. That’s like saying a chicken cutlet is not tasty because the salt is not distributed evenly,this fat part has more salt than meat. So that it’s definitely not nice to eat.”
Andrew V. Uroskie
OMG LOL!! It’s like the Scientologists whenever the O2 is discussed! If you don’t praise us, YOU’RE WRONG. Not only that, you’re wrong and you’re stupid. And you also don’t know what you’re supposed to like, which is what we like, which is the O2. ABX, neutrality, wire-with-gain, eternal life, L Ron Hubbard… Bah ha ha!
Andrew V. Uroskie
And just like the Scientologists, watch a million followers descend on this forum to “defend the faith!”
Bootney Lee Farnsworth
I recognize that I’m a bit late to this party, but I’d nonetheless like to share my views.
I think some of the objections to this review simply stem from the mindset it betrayed. One may choose to rely on more than science when judging a product, but that doesn’t mean science can be altogether ignored.
For instance: If an amplifier is verified to be completely transparent, the phrase, “I found it lacking X-attribute and Y-attribute,” is no longer valid. Accuracy demands such statements be phrased more like, “I found it lacked the added X-attribute and added Y-attribute to which I’ve grown accustomed.” Otherwise, you’re really just saying that either the music or headphones, or both, lack those attributes.
In the case of headphones, that could very well be true. But for music? Never. Transparency means that only intentional sounds from the source recording are reproduced. All things being equal, if you find something lacking a particular attribute, you were supposed to find it lacking; it was intentional.
That’s not at all to say you have to like a transparent reproduction of music, but transparency and its implications should be acknowledged.
Put another way: you cannot blame a ruler if you don’t like the measurement.
In my mind the thing about evaluating the O2 is basically price -vs- performance, or where does it fit in the market and just how critically do we have to examine this 100-plus dollar amp? I don’t see a problem running a billion dollars worth of measuring gear on it and printing the results, but still, after getting those results, I don’t think it merits a lot more than 100 dollars worth of evaluation unless there’s something unusual in the features or sound. And if there is something unusual, it’s still 100 dollars. If I bought a car for $20k that had a feature that was previously only available in a Rolls, would it be reasonable to judge the $20k car or even that specific feature against the Rolls and its feature? A comparison would be good, but it shouldn’t have to be contentious when you’re only paying the lowball price.
Bootney Lee Farnsworth
For the most part, I agree with you. Beyond comparing the O2, or anything else that’s targeting transparency, against other products with similar goals, I don’t even see the need for a review. I’d compare it to a well known transparent amp, and if it measured up, I’d call it transparent and then go on about my day.
However, comparing it to a cMoyBB is inherently unfair, because they were designed with different goals. That’s why saying the O2 lacks the bass of the cMoyBB is nonsensical. Maybe it’s just down to semantics, but the more accurate statement is to say that the cMoyBB has more bass than the O2.
Once any audio gear is established as transparent, it becomes the benchmark by which others are compared, not the other way around.
Makes sense – thanks.
Bootney – you say ” For instance: If an amplifier is verified to be completely transparent, “.
How is an amplifier verified to be completely transparent ?
Do you hook it up to an Acme Transparency Detector Version 3 ?
How do you know if the Acme Transparency Detector is working correctly ?
Sorry, I rely more on science that you do, so I know that there is no such thing.
Bootney Lee Farnsworth
I would think a man of science such as yourself should know that, although the Acme Transparency Detector obviously doesn’t exist, there are other instruments which do exist and can easily be used to measure a number of parameters associated with what people can and cannot hear. There’s no mystery.
The only mystery is how you know that those parameters are associate with what people can and cannot hear ?
You can quantify each, but how they sound all mixed together with the music will need a quantum computer to sort out. If the program can be written to do so.
I think you are also missing the point – how would the computer know which measurement was audible and which was not ? Especially in combination with each other ?
Of course, the answer is that the computer cannot know – it can only be programmed by human beings.
And, if you had an island filled with the most brilliant computer programmers and electrical engineers, and every one was deaf, it would be impossible for them to create tests that determine whether an amplifier was transparent. Literally impossible.
People keep putting the words “science” and “measurements” into their sentences to try and convince themselves that there is something scientific going on, when there is not.
So they would still need their hearing to confirm their measurements. But wouldn’t hearing bias their measurements? Is this saying that science is still beholden to philosophy?
You can establish thresholds of audibility of the different “inaccuracy’s” (noise,distortion, FR and timing errors) of the signal and then compare them to the output of the amplifier. If the amplifier doesnt “add” anything to the sound then I don’t see why it could not be called “transparent”.
How do you know that those are the inaccuracies of the signal ? How do you know that there are not interactions between those four quantities ? If noise is 4 and distortion is 10, it may be more audible than just noise at 4 or distortion at 10 separately. Or noise at 4 and distortion at 10 and timing at 0.11 vs noise at 6 and distortion at 3 and timing at 0.28. And so on. The idea that there are some tests that can establish transparency comes from the idea that “there must be tests that can establish transparency” and NOT from anyone with experience with audio and tests.
I’m left with a ‘meh’ feeling after reading this review. But that’s fine. It’s happened before and will happen again. I come to Headfonia for the excellent photos, and always will.
At a recent Headfi meet, an O2 got plunked on top of my part of the table. It was a wonderful (and huge) surprise. At first, I thought it wasn’t a battery powered amp (certainly you can forgive me). It’s huge.
I tried it with Fostex TH900 and my trusty FitEar ToGo334. Yep, ‘black’ background. Noise noise at all anywhere. I used low gain with both at first, and with small volumes, high gain just to see, but I am NOT a listener of loud music. I kept low gain for both headphones.
I think this opinion has come out quite a few times in the comments to this review, but I’ll reiterate: the O2 disappears. I don’t mind amps that have sound, and indeed, have praised a few at TouchMyApps, but the O2 was an epiphany after rounding the table by some other amps, all of which cost at least twice. There were one or two other amps that almost disappeared, or maybe they did.
Meet conditions aren’t the greatest and we weren’t able to volume match.
Indeed, the O2 disappeared. I do agree with Mike that it would be better to have a 6,3mm jack, and maybe RCA inputs. Also, on the rear, the DC input would make it more wieldy.
But, come on, it’s a 50$ DIY amp. Or a 150$ amp all built. Incredible to say the least.
Thanks for sharing your impressions, shigzeo.
I am waiting for an o2 with 6,3 mm jack and rca on the back, there are different build of this amp. This one I take is a semi desktop.
Hillarious! TY :))
One more thing that has been left out of the comments, certainly by the so-called objective people, is illustrated so: A couple years ago in Ohio we were walking in the woods, in winter when there were no leaves, and my wife saw a deer. I said “Where?” She pointed straight ahead and I couldn’t see it. After about 2 minutes of pointing I finally figured it out. And it wasn’t all that subtle. If you knew what to look for it was right there, 30 feet away, plain as day. And so assuming you have high enough rez tracks to hear a difference, you still have to learn sometimes what to listen for.
I am who built one based on the released PCB and list of component. i do some modification in battery section, in coupling capacitors, and add a massive alu case, a 3 pin XLR for output, mini-XLR for B. charging, and two of Ag plated RCA for input.
With AKG K240 (monitor 600 ohm) can it driven to comfort listening level and above.
With a various audio source it can do lot better than i want to take down the cups before the battery down.
I think the battery quality and thees connection terminals was the Achilles point of this this OP-amp based HeadPhoneAmp. Take care of that and find a right music with O2.