Disclaimer: I received a loaner sample of the 627 directly from Portaphile.
My encounter with the Portaphile 627 started with many emails with Cesar, the man behind Portaphile. It didn’t take long for me to understand that Cesar only had one goal in mind and that is to produce the best sounding portable headphone amplifier there is.
A three channel design based on the popular OPA627 op-amps, combined with three BUF634, one for each channel oops, sorry TWO BUF634s for each channels for a total of SIX buffers in a single ended configuration. That’s crazy, considering the powerful Ibasso PB-2 amplifier only has one buffer per channel, for a total of four buffers in balanced mode. Combined with a Jung Multiloop topology, this amp should have it all: both high quality sound as well as power output. For the record, this amp powers the Hifiman HE-6 so effortlessly at only 11 o’clock at high gain. Insane power levels.
When the 627 arrived, I tried it with a few stuff that happens to be lying around in the store, and I was so surprised in hearing the once unlistenable Sony XBA-4 IEM (I called it the IEM with the boombox tuning in the UE900 review) being transformed into a such musical sounding in ear. The Portaphile has this way of smoothing out the treble (not cutting off or rolling off the treble), and filling in the recessed mids of the XBA-4 very nicely. It doesn’t boost the bass and I’m glad it doesn’t since the XBA-4 already comes with plenty of bass. The other headphone was the Sony SA3000 which is the mid-line model from the famous SA1000-3000-5000 model. Like the XBA-4, though not to such extremes, the SA3000 was also weak in midrange body and a bit harsh on the treble. And once again the 627 does its magic, making the SA3000 even more enjoyable than when I paired it with the ALO National (which is one of the best SA3000 pairing I’ve heard).
Though I compared the 627 to some other amps like the ALO National and Matrix Portable, it was the comparison with Ray Samuel’s SR-71A that really got me excited about the 627. I’ve long regarded the SR-71A as one of the best single ended portable amps and still is today, and once I’ve heard how the 627 fares with the SR-71A, I realized that it’s time to bring out all the other big amps to compare it with the 627.
Let’s start with the SR-71A.
627 vs RSA SR-71A
The first thing that stands out is that the 627 has a much bigger soundstage which was mind blowing to me. I knew that the 627 has a big soundstage from the first time I’ve listened to it, but I didn’t thought that the difference is going to be this dramatic since the 71A has always been a respectable performer there.
Transparency is better on the 627, especially on the bass region where the SR71A though has a much better low end body, is significantly muddier on the lows. Midrange and treble is a knock out with the 627. Had it not for the powerful bass impact of the SR71A which the 627 really don’t hold a chance to, it would’ve been a total knock out!
627 vs ALO Rx Mk3B
The Rx line up has always been a spacious sounding amp but again the 627 exceeds it. Not only that but the soundstage depth on the Mk3B is relatively flat while the 627 is more three dimensional and is very natural. Detail retrieval and transparency is also superior on the 627. The midrange is smoother and more natural on the 627. The Mk3B is still a great amp even if I’m only using its single ended circuitry, but the 627 is overall the better amp if you’re talking about refinement, resolution and soundstage.
Bass impact is softer on the 627 but with better detail and transparency. This is the sort of bass that I enjoy for Blues and Jazz while faster paced genres like Rock is better on the Mk3B’s more powerful bass impact. The 627 is not a bass light amp or a bottom light amp, it’s just that the relaxed bass is always a part of the OPA627’s character. It’s extremely special in the mids though, very vacuum tube like in that regards.
627 vs Apex Glacier
I just received the ultra slim Glacier and decides to throw it in this comparison.
The sound quality of the Glacier is very solid and definitely among the best sounding portable amps out there. Single ended, and talking purely on sound quality and ignoring power output (though the Glacier is actually quite powerful), I would immediately rank it as better than the Rx Mk3B’s sound quality (ignoring the balanced features on the Mk3B). The Glacier is very spacious and the detail retrieval is amazing, and the closest to the 627 among all the other amps I compared here. The sound is forward and lively, similar to how the Continental and RX Mk3B are which is quite a contrast from the mellower 627. However when I listen to the sound as a whole, the 627 is far more natural sounding and closer to a big desktop amp. Coherence from top to bottom is top notch with the 627, soundstage is very natural (I’ve said it for a few times now, this is among the best aspects of the 627).
627 vs ALO Continental
The ALO Continental is the only amp I find that rivals the 627 in terms of sound quality. On my first impression, the 627 is superior: wider soundstage, transparency and detail retrieval, refinement, and bass detail. However the Continental also posseses a few strengths of its own that the 627 doesn’t have: the sound is very clean and crystal clean on the Continental, whereas the 627 is quite grainy. Soundstage though narrower than the 627, has a much better depth on the Continental. Overall I do prefer the soundstage on the 627 as it sounds more natural. Vocals are smoother and mellower on the 627, and I know people who digs mellow sounding tube would prefer that sort of a vocals. I, however, like the more forward, crisper vocals of the Continental. It gives me a closer, uncolored vocals which I like better than the more relaxed vocals on the 627. On bass, I enjoy the punchy bass on the Continental better, but low bass presence is much better felt on the 627.
At the end, it comes down to individual’s preference and music choice. I feel that overall the 627 is the more refined, the more upscale amp. However the pace is a little too relaxed for me, a little lacking PRaT. The Continental does the toe-tapping factor better for me, faster pace, more upfront sound, it falls in line better with my preference, but everytime I go back to the 627 I can’t help but feeling how narrow the soundstage on the Continental feels.
Headphone pairings report on the next page…
Julius
RIP my wallet. At that price, I need to sell off a few things. I’d like to sell off my Vmoda M100 and a few other headphones I own just to afford this amp. Ugh…this hobby. Thanks for the nice write up, I’m sure I’ll be pairing this amp with my Hisound Nova Dap very soon.
Mike
You’re welcome, Julius!
sygyzy
I really wish you would link to products and manufacturer websites rather than linking to tags. That’s fine that you do it once or twice but neither in the header or footer of this review do you ever include a link to the the product. No, it’s not hard for someone to google it but the point is they shouldn’t have to. I feel like this is very basic website 101. I love your views, follow you on Facebook/Twitter and subscribe to you feed so sorry about the rant but I think proper information and linking, especially in a review, is something you should adopt.
Mike
That’s a very good suggestion actually. Gimme 5 minutes and I’ll do it.
Ahmad Ar
Nice review mike
Mike
Thanks, Ahmad!
Isaiah Mackler
Great write up! Looks like an amazing amp!
Mike
Thanks, Isaiah!
Gorboman
Okay, now the price tag made a little bit more sense. So it’s more of a transportable then regarding the battery life?
Mike
Yes transportable though I’m persuading Cesar to release a bigger 627 with a bigger battery. He can double the thickness of the case and I would still happily use it given the sound quality.
Gorboman
Just a thought, smartphones nowadays can cram a lot of juice into a slim form factor. I wonder if Cesar can find a way to do something similar.
Mike
The power comes from those BUF634s I believe.
Julius
Mike, you mentioned the lack of bass punch being a little upsetting. How does the amp respond if the source is outing some solid bass?
Mike
Even on recordings with strong bass, I don’t feel that the punch is enough coming from the 627.
audionewbi
” As I mentioned earlier, it completely transformed the bright and nasty Sony XBA-4″
Sold 🙂
Mike
I know! The XBA-4! Can you believe it?!
ertai
Does it mean it has a low output impedance?
I totally agree with the battery life part, it was really the main reason preventing me from seriously considering it despite all the positives
Btw, may I know which DAP you were using when reviewing the amps? Thanks : )
Mike
I think the effect of output impedance on the overall sound is very hard to predict.
The source I use for this.. Altmann Tera & CLAS and the Dacport LX.
audionewbi
Going to be a long while before I can purchase this. Just bought the ES10. But worth the wait 🙂
paconavarro
Very interesting little amp…
Mike
Yea had it not for the sound, I wouldn’t even looked at it. Looks like just another offering in the sea of portable headphone amps out there. No fancy enclosure, no thin-slim build, no bells and whistles.
GraveDancer
Mike:
Great Comments!
Any comparisons to the L3? (I have the Triad L3).
Just wondering as the time of giving is around the corner and the 627 could be a good gateway drug for a music lover and a lower entry point.
Mike
I don’t have the L3 around, but the one thing that sticks to mind about the L3 is that its bass impact is extremely good and oh soo addictive. Dynamics wise the L3 is also superior.
Sound signature wise the L3 is more forward, faster pace, while the 627 is more laid back and relaxed.
I drew some comparison of the L3 to the ALO Continental here:
http://www.headfonia.com/the-amp-that-makes-me-feel-so-powerful-triad-audio-l3/
Valentin Hogea
It feels good that it’s inferior to the L3 though. Means I don’t have to get it! 😉
Tim Ashlin
Hi Mike, Nice review! Just wondering how you think the 627 compares to the Pico Slim (in terms of sound quality/presentation)
Mike
Hi Tim,
The 627 is much bigger sound than the Pico. The sound is far more natural on the 627.
Ken Stuart
How does this compare to similarly priced desktop amps ?
Mike
Interesting.. I haven’t really compare it.
Perhaps to the Graham Slee Novo?
Lee Chuan
Wow I tried the Govibe portatube today with my Amperior and was finding a substitute mainly due to weight and battery. This seems similar but still have the cons that stop me from parting my $. Is there any other less pricey options than these 2?
Mike
What were the cons? And what sort of amp are you looking for and what budget?
Amperiors shouldn’t need that much of an amp. Cmoy or PA2V2 should do fine.
Lee Chuan
Actually the cons for me were the weight and the price 😀
Due to the pretty wide range of genre I’m listening to, I am trying strike a balance across all aspects.I have the cmoy but i find it too bassy. Clarity was amazing with Portatube. There was this “sparkle” or brightness in the music which I find it pleasing.
Soundstage improvement was primarily what I’m looking for, though it seems stupid or impossible for such a small housing. I’m trying the National soon.
Lee Chuan
Btw the volume knob looks the same as the cmoy lol.
Kelvin King
would the portaphile 627 pair well with the Beyerdynamic T1?
Mike
Kelvin,
The sound signature seems like a good match for the T1 but I don’t have the T1 around to test it with.
Kelvin King
how about the DT770 A/E?
Eyal Sade
how does it fair against Leckerton 6s mk2 ?
Johanes-Fernando Nengkono-Neng
Interesting amp Mike, I was dreaming to pair it with my 2nd xba4 which I bought from your store…
how this amp comparison to ibasso pb2?
can you sell yours to me with half price? hahahaha, just kidding…
regards…
Johanes-Fernando Nengkono-Neng
Nice review Mike, I was dreaming to pair this amp with my xba4 which I buy from your store.
How this amp compare to ibasso pb2?
May you sell yours to me for half price? hahahahaha, just kidding
regards…
Mike
Please read my multi-amp review which includes the PB-2.
I compared it there to other amps like the SR-71A.
http://www.headfonia.com/the-usual-suspects-12-portable-amps-compared/
Mike
Please read my multi-amp review which includes the PB-2.
I compared it there to other amps like the SR-71A.
http://www.headfonia.com/the-usual-suspects-12-portable-amps-compared/
Chris Wong
Nice review Mike, in your opinion, I have a Shure SE535Ltd IEM and Denon 7000, is the 627 or the ALO Continental or ALO RX3 a better amp for SE535?
Mike
Ugh.. I know the sound of the 535LTD but it’s not something that I’m too familiar with. The Denon, again I wouldn’t know. Sorry Chris.
Loïc Labbé
Nice review Mike, this product seems really amazing!
However, on its website, Portaphile is talking about a little 4 hours battery autonomy. In this case should we talk about a “portable” headphone amp? Did you have the opportunity to check this point?
regards…
Mike
Yes I think I did mention about 4 hours battery life on the review.
Joseph
Maybe not fair… but since you compared so neck&neck w/ the Continental, any thoughts vs. the ALO PanAM?
Mike
Well.. you can always compare anything but it’s not going to be very relevant.
The PanAm is somehow like the Continental except on the bottom end where the PanAm does better. Other than that the soundstage is also bigger on the PanAm.
I think aside from the sound signature difference, the one noticeable thing I hear from the PanAm is the blacker background and the much cleaner, grainless sound.
For driving the Hifiman orthos, however the Porta does a much better job.
Cheers
Laurencewayne
Mike- I’m still trying for lushness in my Fostex TH900. Since it’s warm & bassy at the bottom but a bit strident at the top, would the Portaphile 627 be a better match then the Fostex HP-P1? Based on your review (as usual, cogent) this amp might compliment. And a very Happy New Year…your site, attitude, responsiveness and patience is remarkable.
Laurence Wayne
Mike
Happy New Year too, Laurence.
Yes the 627 is worth to try, reading from what you wrote about the TH900. I’ve listened to the TH900 out of the Fostex HP-A8 and I have to say I agree with the complaints you have.
Mohammad Ashraf
Hey just wanted to say that there is going to be an update one coming out, pre-order is on, cant wait 🙂
Mike
Yes, with a bigger battery.
Jomyr Aquino
Hi Mike,
I enjoy reading your articles. I was wondering, what are your thoughts on pairing this with the AKG K550? Out of all the portable amps you have tested with the AKG K550, Where does this rank? What do you think would make the best pairing?
Hope to hear from you soon.
Mike
Jomyr,
I think it is a decent amp for the K550.
I haven’t been listening to the K550 that much lately so I really can’t comment on amp comparisons with it.
Perhaps some of the other readers can help?
Jomyr Aquino
Hi Mike,
Thank you for the response. It’s ashame that the 627 pairing with the AKG K550 would only be a decent pairing. I was kind of excited that the pairing would be great. You have mentioned that the ALO RX MK3-B pairs well with the AKG K550. I would love to hear your thoughts on that pairing.
Jomyr
Michael
Thanks for the review, Mike. What do you think about pairing it with Sony MDR-MA900?
Mike
It’s a really nice pairing with the MA900
blake
hey mike,
i would like to know how this amp compares with the asgard, and/or other desktop amps at this price range. Is desktop too much for the 627?
-blake
Mike
It’s definitely better than the asgard both technicalities and power. Sound signature differences aside.
I think it’s almost like the graham slee solo 2 amp.
Ryan
How does the Just Audio AHA 120 compare to the Portaphile 627? Which one is better?
Mike
627: more power, bigger soundstage, more mid centric, mellower
AHA120: more linear, overall fuller sound
dalethorn
The part about “quite grainy” is puzzling. Why would that not disqualify this amp?
Mike
Huh? Sorry I don’t understand the question
dalethorn
I assumed if the sound is grainy, it’s not clean, and that would be bad for music. So it’s possible for sound to be grainy and it’s still OK for music?
Mike
I think grain affects the technicalities score, but very rarely the musicality.
Zana Deux is extremely grainy
Senn HD600/650 is also grainy
Senn HD25-1 is grainy
Vinyl is grainy
Most great Jazz recordings are grainy
The list could go on and on
STARSTERN
my impression ;that the DACport LX is kind of your best portable dac ,while the Portaphile 627 is kind of your best portable amp ;now: for the price range of these both ‘ or lower ,are there any dac/amp combo which would meet their sound quality ?? and may be of more compact in size ?
STARSTERN
Portaphile 627 gets amazing reviews at forums as the best of the best ;would you tell us your impression of it in compare to really good amps as the soloist and crack and even alo six ?
Mike
Different level.
Portables can’t compete with good desktops in terms of dynamics and range. That’s just two parameters.
STARSTERN
let me take the question in another direction now ;
how would you put the difference between a cypher labs theorem 720 dac/amp
to a portaphile 627 amp combined with dac port lx !?
Mike
Theorem, more resolving, more dynamic, more impact.
Portaphile + Dacport, softer, more spacious, mellower.
Luke Ma
how does this amp compare to desktop amps? is it hopelessly outclassed or can it still play?
Mike
Luke,
It’s better than many of the cheap desktops.
Luke Ma
so, can it top the crack and the torpedo, or is that too much
Mike
Depends on the headphone.
The Crack is very good for the 300 ohm Senns. The portaphile however drives orthos better than the Crack.
Chris Vanaman
Incredible review. Is it fair to say this 627x is a great match with the Beyer T90?
I’ve narrowed my choices to 2 amps- 627x and Pure II. I just don’t know nor do I have access to test. 🙁
Thanks for great review, Mike.