The Sweet Sound of Tube: The ALO Continental Amplifier


I’ve spent a few weeks now with the Continental, and I can tell you outright that it is perhaps the best sounding portable amplifier that I’ve listened to. Which is awesome for me because it’s so good sounding, but it’s a bit of a shame since they are no longer available to purchase. Yes, in a mere short 1-2 months after the Continental is released to the market, the amplifier is no longer in stock, and I don’t have a clue if there will ever be another batch of Continental. Nevertheless, I love talking about good sounding gears, and so here it comes.

When I did the Usual Suspects article, at the end I would come up with a few short conclusions:

  1. The IEM amps are good for IEMs. The Mustang, the Shadow, the Pico Slim et cetera. They sound really good, and the Mustang actually has enough voltage for big headphones as well, but when it comes to overall power and impact of the bigger amps, they just fall short.
  2. The Balanced amps gives a higher power output than the single ended amps, and balanced drive tend to expand the soundstage width and increase bass, but in overall fidelity and refinement, they tend to fall short.
  3. The Slim amps were good, and sound signature/tonality issues aside, I would rank the slim amps, based on technicalities, as such (least to best): Headstage, TTVJ, ALO Rx.
  4. The Big amp group had the edge in sound quality, but were big and bulky to carry around. Among these, I found the RSA SR-71a to be the best one.

There is no point making a comparison to the IEM amps since the bigger amps almost always have the better impact and sound quality (only bad potentiometers that makes them unusable with IEMs). Likewise the balanced amps, since they can’t match the fidelity of unbalanced amps. So now I’m only looking at the Slim amps and the Big amps. Personally, I think that the RSA-SR71a is better than the ALO Rx except that the RSA doesn’t come with rechargeable batteries, which is a big necessity nowadays. I would have loved to compare the RSA SR-71A to the Continental, but I can’t get one during the time of this review (though if I can on a latter date, I would add that in as an update).

The next one in line, therefore, is the ALO Rx Mk2, which I am going to compare to the Continental. The ALO Rx Mk2 had this signature lively and spacious sound, clear and grain-free with an awesome, deep hitting bass impact. Though tonality wise I still prefer the TTVJ Slim due to the fuller mids, the TTVJ was a little grainy in sound and was not as spacious sounding as the ALO Rx. I still think that the RSA SR-71a is better than the ALO Rx Mk2 in this sense, as it manages to pull out both a very spacious soundstage and retain the typical weighty full bodied sound that RSA amps are famous for. But again, since I don’t have the SR-71a around, I would just use the Rx Mk2 (thanks to Peter for his Rx Mk2 loaner).

Versus the ALO Rx Mk2

Comparing to the Rx Mk2, it’s clear that the Continental has the upper hand almost entirely. Ive always thought that the Rx Mk2 is a spacious sounding amp, but the Continental makes it sound so flat and two dimensional. It’s not even a close fight, the Continental totally trumps the Rx in soundstage. Not only that, but midrange body, which is the Rx Mk2’s weakest point, is something that the Continental happens to be very very good at. The midrange of the Continental is easily the best I’ve ever heard on a portable amp — better than the TTVJ Slim (and the TTVJ portable tube too), better than the RSA Mustang, better than any of the amplifiers I’ve reviewed on the Usual Suspects. You get a full, sweet sounding midrange with superb clarity levels. No muddy, overly thick, slow sounding midrange here.. just pure honey sweet midrange with superb clarity. Then comes the treble areas. The Rx Mk2 is pretty good with treble, but again the Continental is better. Not only is the treble cleaner and clearer sounding, but it also extends up in a much smoother gradient, where the Rx Mk2 sounds more like an abrupt cut off of extension. Now I realize that the solid state Rx Mk2 may actually have the higher treble extension because solid state normally extends further, but my ears can’t pick up the roll off point if the Continental indeed has an earlier roll off. And the point that I’m saying is that the manner at which the treble rolls on the Continental is much smoother, gradient wise, than what I hear on the Rx.

Dimension is almost identical to the ALO Rx (except obviously thickness). The length of the amp (not pictured) is pretty much identical between the two amps.


Like all other tube amps, when it comes to the bass section, the Continental follows the same pattern like the rest of other tube amps. Sweet full midbass punch, but not so much happening on the low bass. Bass extension is good, but the problem is that there is no action happening on the low lows. This is where the Rx shines. Clearly, you get a deeper hitting bass with the Rx, and also a faster bass speed on the Rx than you do on the Continental — so bassheads is probably the main group that should stay away from the Continental, or any other tube amps for that matter.

Now if you zoom out and take a look at the sound of both amplifiers from a more macro view, then the Continental looks like one sweet coherent sound with a slight focus on the mids but extends out to the highs and lows gracefully. The Rx Mk2, on the other hand, looks like two separate acts going on in the treble and the bass, with a pretty thin midrange to connect the two areas. From that view, it’s hard to see the Rx Mk2 as the better amp. In fact, the qualities with which I describe the Continental puts it in a position well ahead than sub $500 desktop amplifiers, even desktop amplifiers, as long as we ignore the overall power output ratings. This is one of the best portable amplifiers I have listened to. Definitely up there with the RSA-SR71a and the LISA III.

The internals. You can see some glue is used to minimize movements especially with the tube.


Headphone Pairings

The Continental works well with the big full size headphones. I’ve used the Continental with the Sennheiser HD800, Beyerdynamic T1, Hifiman HE-500, and the Audez’e LCD-2. I think it pairs really well with the HD800 and the LCD-2, though okay with the T1, and slightly under powered with the HE-500. With the T1, the Continental had a good thing going with the treble and midrange, but I don’t think it has enough bottom end body to keep the sound planted. RSA amps are probably the better choice for the T1 in this case. As for the HE-500, yes you can use the Continental to get it up to a decent loudness level, but for moderately high volumes, you can feel that the Continental is running out of steam. So in a way, while the Continental comes with plenty of voltage swing to get the loudness level up, I don’t think the hybrid tube circuitry has enough juice to deliver the necessary power for the HE-500.

For IEM use, it would depend on the sensitivity of the IEM you’re using. For instance, with the JH5Pro which is a really sensitive IEM, 8 O’clock would give me reasonably loud levels. With the Hifiman RE272, I would listen at around 11 O’clock. Using the amp with a sensitive IEM like the JH5Pro is actually not a big issue, but just don’t expect a very delicate control over the volume.

Day to day use

Being a portable tube amp, there is some concerns with tube microphonics, heat level, and battery life. One of the issues that I find on the TTVJ/Millet portable tube amp was that the tube microphonics really doesn’t want to go away. Tube microphonics happen when you are using the amplifier on the move, and as the amplifier moves around in the pocket you would hear a faint sound similar to if you give a soft knock on a wine glass. The ALO Continental, however, manages to eliminate this problem mostly, although you still get slight microphonics with very sensitive IEMs like the JH5Pro. Heat level is actually quite low, much lower than say a Hifiman HM-801 player. Battery life is just okay at ~8 hours. It’s probably not the best for portable amplifiers, but I’ve learned to live with that sort of battery life, since a lot of the big-sound portable gears also run around the same ~8 hours battery life (the Hifiman HM-801, the Cypher Labs AlgoRhytm Solo, the Fostex HP-P1).

The Cricket LOD

ALO also sent me their tiny cricket LOD, which I found to have a perfectly cut length for use with either the Continental or the Rx Mk2 amp. The cricket LOD uses three 22AWG ALO SXC wire which is easily the best sounding silver-plated-copper wire I have ever listened to.

The tiny Cricket LOD.


Cricket LOD use with the ALO Continental.


Cricket LOD use with the ALO Rx Mk2.


End Words

I really don’t know if ALO is going to release another batch of the Continental amp, but my reviewer ears tell me that this pocket amp is easily the best portable amp I’ve ever listened to.


Sadly, out of stock, but the product page is here at ALO Audio.

Gears used for review

Ipod, CLAS, ALO Rx Mk2, ALO Continental, Sennheiser HD800, Audez’e LCD-2, Hifiman HE-500, Beyerdynamic T1, Beyerdynamic DT1350, Sennheiser HD25-1, Superlux HD661, JHAudio JH5Pro.


Rate this review



  • Reply March 25, 2015

    Steve Harris

    ALO Audio has made a few available here:

  • Reply December 1, 2012

    D.r. Hilerio

    I have the ATH-W3000Anv. Is it a good pairing with the The Continental? Would the Pan AM be much of an upgrade?

  • Reply May 18, 2012

    Tony Jin

    How would you compare this to the Schiit amps? I’d use it quite often at home, but still would like to bring it to the office from time to time. Probably paired with the HD600, HD25, or Vsonic GR07 (+ YH-3!).

    • Reply May 18, 2012


      While I like the convenience of desktop amps when used at home, I’d take the Continental over any of the Schiit tube amps.

      • Reply May 19, 2012

        Tony Jin

        Wow. That says a lot. Time to start saving up! 🙂

      • Reply May 19, 2012

        Tony Jin

        The same can’t be said for the National though, right?

        • Reply May 19, 2012


          No, the National is good but it’s just different.

          • Reply May 20, 2012

            Tony Jin

            Ok I’ll look more into it. Thank you very much!

  • Reply March 24, 2012

    Chong Yuxuan

    Wonder how the ALO Audio National will compare to the Continental since they’re supposed to have the same sound signature, except that the National is solid state.

    • Reply March 27, 2012


      I have yet to get it, but I should have one soon.

  • Reply March 12, 2012

    Victor Halgaard

    Hi there, have you by any chance tried the GoVibe Portatube? If so, how would you compare them? 🙂

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