The Power Pack: ALO RX MK3-B

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Enclosure and User Interface

Looking at the photos of the Mk3-B, I guessed that it’ll be finished in the same hairline anodized finish as the Mk2 and CLAS portable DAC. Instead, the Mk3-B comes in a smooth semi-gloss paint finish similar to the National amp. I have no idea why ALO did that, and would rather they keep it uniform  as the finish on the Mk2 and the CLAS. After all, I appreciate the fact that they stick to the same enclosure dimension (and even design), as it makes for a good looking stack with the CLAS portable DAC. Indeed I find it impressive that ALO was able to manage the same enclosure size, while doubling the amplification circuit for a balanced amp, and I suppose a higher capacity battery as well. One thing worth noting is the power indicator light that conveniently points out the state of the battery level through its color (Blue = Play, Green = Charging, Yellow = Low Battery, and Red = Very Low Battery/Charge Now).

One thing that you have to know about the front faceplate layout is that when you can’t plug in two headphones into both the single ended and balanced output port at the same time. This is due to the design of the 4-pin connector used, which physically blocks the 3.5mm single ended port.

I always prefer conventional shaped volume knobs to anything else, and the two knobs on the Mk3-B’s front faceplate is a big win for me.

Balanced Input/Output

The Rx Mk3-B comes with balanced and single ended ports both on its input and output sections. That means you can use either a balanced or single ended source, to drive either a balanced or single ended headphone at the output. I only used the CLAS throughout the time of this review, as I didn’t have any portable balanced DAC around. I did alternate between the single ended and balanced headphone out as I didn’t have a balanced cables for all of the headphones I use (the AKG K550 for instance).

One thing that surprised me is that there is no difference in loudness level between the single ended and balanced outputs. Usually, due to the balanced out having twice the effective voltage than the single-ended, you get higher loudness level on the balanced out. I asked ALO about this and they did intentionally raise the gain of the single ended port so that it matches the balanced out. Indeed the single ended out sounds great and there is no reason not to use it, but this is a balanced amplifier after all, and I figure that most people will want to use the balanced port most of the time.

Headphone Pairing

Having such a powerful output, I find that the only problem I find is when using sensitive IEMs. The lowest of the three gain settings is not low enough to provide good volume control with my JH5Pro or Shure SE215 IEM (out of a CLAS portable DAC as the source). I can listen to it just fine on moderately loud volumes, but for low level listening I would get imprecise volume tracking.

Driving the Sennheiser HD650 headphones out of the balanced port, low gain setting is enough for most recordings except for classical. It doesn’t quite have the midrange quality of the hybrid tube Continental amp, or the full bodied mids of the National, but the Mk3-B was able to pick up the pace of the HD650 and make it a quicker headphone than when driven on single-ended amps.

The real magic happens with the Hifiman HE-6. Not only does I have no problem getting enough loudness on the medium gain level, but the amp also has a really good synergy with the HE-6. I’ve always been a bigger fan of the HE-500, but that’s probably due to the fact that most amps I review can’t drive the HE-6 right. The HE-500 is much easier to drive than the HE-6, but in this case, I can see why the HE-6 remains the flagship model, it’s just far more impressive on the Mk3-B.

I didn’t have an LCD-2 to test the Mk3-B with, but based on the results with the HE-6 and the HE-500, I think the LCD-2 should be an easy load to the Mk3-B.

 

End Words

I still can’t fathom how the slim Rx Mk3-B amplifier is able to drive the Hifiman HE-6 so brilliantly. I’m not saying it defies the law of physics, but I know how difficult it is to drive the HE-6 and I’ve seen the majority of desktop amplifiers, even BIG ones that fail to deliver the job. The Mk3-B not only drives it with sufficient authority, but it strikes such a beautiful synergy with the Hifiman as well. I’ve tried some speaker amps that have plenty of power to drive the HE-6, and while they still have more oomph than the Mk3-B, the sound synergy is not always very good. The Mk3-B is not like that. Good power with plenty of punch, and with a good synergy going on as well.

The race for the most powerful headphone amp in the market is still on, and currently I declare the ALO Rx Mk3-B as being the most powerful of them all as it convincingly drives the Hifiman HE-6.

 

Gear used for review

Ipod Classic, Cypher Labs AlgoRhythm Solo, Hifiman HE-6, HE-500, AKG K550, Sennheiser HD800, HD650, Philips Fidelio L1, Shure SE215, JHAudio JH5Pro

alo_rx_08 alo_rx_07 alo_rx_06 alo_rx_05 alo_rx_04 alo_rx_03 alo_rx_02 alo_rx_01

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  • http://www.headfonia.com Mike

    If you happen to own the Hifiman HE-5 (the original). I have just tried it on the RX Mk3-B running balanced, and with the Hifiman leather pads, the sound is absolutely amazing. The best I’ve heard the original HE-5 with. Obviously the leather pads help in taming down the treble, but the amp strikes a brilliant synergy as well.

  • http://www.facebook.com/people/Victor-Halgaard/1269871108 Victor Halgaard

    Hmm, for the HD800, how would you compare the Mk3 to the SR71b? I really like the hd800 because it has the pace, punch and attack of a grado (almost) so its good for metal, but also an incredible amount of detail etc. so it is good for classic and other genres too. I’m sorta wondering if I should try switching to Mk3 and maybe even switch to a HE6 as well… Any thoughts?
    Cheers :)

  • http://www.facebook.com/profile.php?id=775085491 Steve Wiser

    No mention of very sensitive IEMs and how they fair.

    • http://www.headfonia.com Mike

      I did Steve, please check page two. :)

  • http://www.facebook.com/people/Victor-Halgaard/1269871108 Victor Halgaard

    Is the HE-500 or HE-6 best with this amp? Or to put it differently, can the HE-6 compete with the HE-500 out of this amp? Because having a speaker amp at home, the HE-6 would definitely be the best there… But on the go? :)

    • http://www.headfonia.com Mike

      The HE-6 is much better than the HE-500 on the Mk3-B.

      • http://www.facebook.com/profile.php?id=552764208 Pinoi Sufi

        Mike, so you would say with HE-500 is not the best synergy with Mk3-B? Because currently im funding for HE-500 and go with portable DAC and portable amp. Do you have any suggestion mike? Sorry I’ve been looking for the answer in the net but wasnt any.

  • Trent_D

    You say the clarity is also good with this amp. How were the mids with the K550?

    • http://www.headfonia.com Mike

      I think the mids are okay. Nothing particularly special but not weak either. You need to go with the Continental if you’re looking for nice mids. ;)

  • http://www.facebook.com/peter.huang.58726 Peter Huang

    Hi Mike. I have the National right now, and I’m using it primarily to drive Ultrasone’s Signature Pro (it has the stock single-ended cable). I was wondering if the Rx Mk3 in single-ended mode only
    would be significantly better than the National.

    • http://www.headfonia.com Mike

      Peter,
      It would be an improvement, but sound quality wise it wouldn’t be a big jump. The Rx Mk3’s main strength is the power output, which your Signature Pro doesn’t really need.

      Cheers

  • http://www.facebook.com/scmonterog Susana Montero

    Hi Mike. I’m looking for an amp that works well with my Hifiman re262 and a Cowon c2. My budget is around 200 usd. Could you please help me? I listen classical, electronic and rock music. Cheers.

  • Andre Sneed

    Hey Mike love what you do over there! I’m looking for a portable amp to power my DT990/250 with some umph!! I have a e11 and it doesn’t feel like I’m getting the most out of my cans. I’m familiar with the Headstage Arrow and TTVJ Slim being some of the only portable amps that can drive 250ohm headphones properly. Doesn’t look like the Rx-MK3 will do the trick either… HELP!! :)

  • stan zorin

    “Like all the other balanced portable amps I’ve reviewed, the Mk3-B does suffer from the same shortcomings compared to the best of single ended portable amps. It doesn’t quite have the composure of high quality single ended amps, the mid range, the soundstage depth, image, and coherence…”
    Does the single ended output of this amp have the same sound signature / shortcomings as the balanced output ? How does this single ended output compare to the Alo Continental sound ?

    • http://www.headfonia.com Mike

      Stan,
      The Continental is superior to the Mk3B single ended.

    • http://www.headfonia.com Mike

      Less problems in single ended but if you want to go single ended the Continental is better

  • http://www.headfonia.com Mike

    CLAS is source
    RX Mk3 is amplifier.

    Different things. Having both is good.

    • disqus_0ADxuk4tWH

      Does a source alter what comes out of my digital player, iPod?…I see they sell the amp/CLAS as a package, so I’m curious…are the benefits dramatic?

      • http://www.facebook.com/HaiVNguyen Hai Nguyen

        google dac ( digital to analog converter) understand what it is first and you can find your answer.

  • disqus_0ADxuk4tWH

    Thank you for the quick response…I await delivery breathlessly…

  • disqus_0ADxuk4tWH

    Excuse my ignorance as, I’m a newbie, I don’t know diff betwixt source and amp

    • http://www.headfonia.com Mike

      Ipod, CD Player, Laptop + Medial Player, Walkman, DVD Player, Sony Playstation = Source Amplifier amplifies the signal before it reaches the headphones / speakers.

  • disqus_0ADxuk4tWH

    Hello all….myRx Mk3 has arrived…..but, alas, a cable is missing or I’m unaware of something I should have had…..can someone guide me?….seems I need something to connect Mk to iPhone…

    • http://www.headfonia.com Mike

      Can you take pictures so I can see what you got?

  • disqus_0ADxuk4tWH

    Mike…..I just got my Rx Mk3…all it has is a power cord…there’s nothing to go from amp to source(iPhone, iPad, etc)…I’m not sure how to attach fotos here…ur kind for the response, so thanks

    • http://www.headfonia.com Mike

      Yes you gonna need a cable to hook up the iPhone to the Rx. Better call ALO

  • disqus_0ADxuk4tWH

    Got it….anything I can buy at radio shack or Frys?

  • disqus_0ADxuk4tWH

    Mike…Seems I’m missing a “triple pipe L.O.D”….I wish I would have known, and, it’s another 200…goodness…what have I gotten myself into….thanks for ur time

    • http://www.headfonia.com Mike

      You don’t need to get a triple pipe LOD. The one from Amazon would do as well.

  • disqus_0ADxuk4tWH

    I’ll DEF be looking at that…can a cable that’s an inch long be worth 200 bucks?…I’ll drive around and see if I can find one….uve been very kind…

    • http://www.headfonia.com Mike

      You’re welcome, not a problem.

  • Gauchomb

    Hey mike, this is me, the rx mk3 newbie…thanx again…I’ll prob have more questions in future, I hope I don’t impose

    • http://www.headfonia.com Mike

      Yes, no problem.

  • Gauchomb

    Hey Mike, rx mk3 is just great….size,weight,sound, defintion,amplitude were as good as defined and described…I use beyerdynamics dt1350 for bumping around and ultrasone pro 900 at home…is there something I can improve on?

  • Gauchomb

    Also, I run alot and bought westone ie2s, billed as the ultimate running earplugs…the actual plugs get saturated with sweat and flat out fall of my ear…in my call to westone, I was told that sweat “compromised” the seal of the earbud…do u know any other high end running headphones?

  • Nishy Wijewardane

    Hello Mike, Nice review. I have the HE-6+SR71B as my ‘portable’ gear (and EF6 as my unportable). You clearly say the ALO does a better job and I’m interested though I have no complaints on the SR71B: does the ALO give a better bass (for jazz); is the soundstage wider, does it have more power output, does it have a longer battery charge, and can it run on the same Silver Dragon balanced cables to the HE-6? Also what amps better than EF-6 with HE-6 can you point to? Have you reviewed the HE-6+EF-6 combination?

  • Vincent

    Hey Mike,

    Can you please tell me how far off between the mk3 and the mk1?

    Thanks.

    • http://ohm-image.net/ ohm image

      The one advantage the MKI has is the digital volume control. Smaller size is up to the owner. The digital volume control allows 100% perfect balance at all volumes with every headphone out there. If you are using single ended headphone or earphone set, the performance differences between the two are slim, but slightly in favour of the MKIII.

      The MKI was such a great amp that bettering it is rather difficult. While the MKIII is, overall, a better-performing amp, the MKI is a phenomenal piece of kit that will hammer it to most amps out there.

      • http://www.headfonia.com Mike

        Yeah the Mk1 is special. Maybe talk to ALO to re-release the Mk1. :)

  • George Lai

    Hello Mike, can the same 9V charger be used for both the CLAS and the RX3?

    • http://www.headfonia.com Mike

      If it’s both 9V then yes

  • George Lai

    And the newer model, the B+, is out.

    • http://www.headfonia.com Mike

      Yeah

    • http://www.headfonia.com Mike

      Yeah, bigger battery and supposedly improved sound. I’m still waiting for the store stock to come in.

      • George Lai

        Though I’m already very pleased with my CLAS -R and ALO National and Continental v3 as my main portable, or rather transportable, rigs.

    • http://ohm-image.net/ ohm image

      It is. Both are great amps. If you are going to choose the best now, the B+ model may be the best investment, but if you already have the MKIII, staying the course is a great idea.

  • Pingback: Alo Audio Rx Mk3-b Portable Amplifier 7 mth old, Made in USA, use < 5x, 10/10()

  • http://twitter.com/Pickcick Pickcick

    Thanks Mike.
    Will it be overkill to pair with HD25-1-II?
    Or The Continental is just enough for it? Which pair do you prefer?

  • http://www.headfonia.com Mike

    I would go with the National for hte HD25-1

  • Andre Sneed

    Haha sorry, I read through it fast the first time around and it looks like I was wrong (Very) with thinking that the Mk3-B wouldn’t be able to power 250ohm head phones when you say it can power the toughest cans out there the He-6 which are known for being power hungry.
    My questions is what “Portable” Amp do you think is out there that can power my Beyers (DT990/250) better than my e11 for $300 and under. I originally was thinking about the Fiio e7 or e17 but thought I should expand my search and do it right the first time you know.. Oh, and the only reason why I said it won’t do the trick is because I don’t have $650 to spend on an amp :)

    My sources are:

    iPad 3
    iPhone 4
    Mac Book Pro
    Current Amp Fiio e11
    Pioneer Elite Vsx-32 (Receiver)

    Thanks Mike!

  • Trent_D

    Way to throw out a tease! What is it?

  • Andre Sneed

    Awesome, thank you!! I’ll look into the ALO and also can’t wait to read your review next week. Thanks again for all you help

  • http://www.headfonia.com Mike

    No tease, it’s just that I have to stick to my publishing schedule, but I don’t want him to buy an amp this week only to find out that there is another one next week. Besides I think this one may be a better fit for the Beyers.
    Anyway it’s the Matrix Mini Portable http://headphone-id.com/index.php?attachments/20120618153055224-jpg.141/

  • http://www.headfonia.com Mike

    Alright, Andre. :)

  • Anton Chernyshov

    Thank you! I’ll concentrate on upgrade cable system for my rig then. Any suggestions would be helpfull.

  • http://www.headfonia.com Mike

    Best to get a better source, Anton.

  • Anton Chernyshov

    Like ColorFly or iBasso DX100 ?

  • http://www.headfonia.com Mike

    Yes.

  • Anton Chernyshov

    Thank you! I was just wondering whether a change of the cable system (Interconnect’s + headphone cable) of this rig could add some clarity to the music scene? What’s your take on that? ( Currently i’m using a stock cable setup from Alo Audio: http://www.aloaudio.com/algorhythm-solo-interconnect-cables ).

  • http://www.headfonia.com Mike

    What cables are you thinking of changing to?

    Your current ALO cables are very good already, that’s what I use too for my CLAS set up.

  • http://www.headfonia.com Mike

    Hi Mushu,
    That sounds like a good combo. There are a lot of portable amps out there so you may want to read the pros and cons first. I don’t really think that there is one magic amp that would be the absolute best, especially as the Edition 8 and the HD700 are two very different headphones. The Solo dB should be a good source upgrade though.

  • mushu

    Thanks Mike let focus on the HD700 what amplif. u recommend comb. with the solo dB?

  • http://www.headfonia.com Mike

    To be frank I’m not too experienced with driving the HD700 out of portables. However I just got the Portaphile 627 amp and I think it’s very nice. It fills in the mids and softens the treble, so I think it should match the HD700, but I haven’t actually had the chance to try the 627 + HD700 pairing.

  • mushu

    Thanks Mike
    Do u think Isabellina HPA is over qualified for ipod as a music source? Haim

  • http://www.headfonia.com Mike

    Mushu,
    I have no experience with the Isabellina, but the Ipod is a lousy source even now I can’t bear using it with a portable amp.

  • http://www.facebook.com/haquocdung Hà Quốc Dũng

    Hi Mike, do you think if I get a 3 year old Mk1 for 1/3 the price of the mrk2 atm with low usage is a good deal that will be a good value (SQ over $) for mk1? Thank you.

  • http://www.headfonia.com Mike

    1/3rd of the price is definitely good value

  • Vincent

    Thanks Mike.

  • George Lai

    I think for the price differential, I’ll go with the National for my Solo instead?

  • http://www.headfonia.com Mike

    Sure thing