The Usual Suspects: 12 Portable Amps Compared

SLIM AMPS: TTVJ SLIM, ALO RX, HEADSTAGE ARROW

Moving up from the tiny amps gives us the slim amps, which come in larger footprints, but still remain quite practical due to their thinness. The tiny amps are excellent pairing if you really want to keep things super-compact, as the tiny amps make for a beautiful match with the Ipod Nano or Sansa Clip players.  But since the majority of people prefer the fuller screen Ipod Touch or the bigger capacity Ipod Classic, then the larger footprint of the slim amps actually fit better. The Headstage Arrow has a smaller footprint than the ALO or the TTVJ, but it happens to match beautifully with the Hifiman HM-602/HM-601 players.

All three amplifiers here are the result of years of design improvements, from the days of altoid-cased CMOYs to the current super-slim, digital volume control, rechargeable batteries, and high power outputs. Portability, features, power output level, and sound quality are top notch and are definitely among the best. The implementation of a digital volume control to the TTVJ and the ALO Rx gives these amps the same clear-cut articulation that I’m hearing on the Shadow and the Pico Slim, but with higher power output levels. Given the high quality sound of the three amplifiers, the first question that you need to ask is how each amplifiers are voiced, as I think their sound signature is first and foremost the most important factor when evaluating an amplifier.

The usual suspects for slim amps: (top to bottom) TTVJ Slim, ALO Rx MkII, Headstage Arrow.

Front and back views. That Headstage Arrow is the slimmest amp in this shootout, beating even the Pico Slim.

TTVJ “SLIM” ($349 standard, $449 with DAC)
The easy way to describe the sound of the three amplifiers is that the TTVJ comes with a good and full midrange, the ALO Rx has a spacious open soundstage with a clear treble and bass, and the Headstage is somewhat “in between” the two with its flatter tonal balance with a slight tint to a dark signature.

Personally, I enjoy the TTVJ the most out of the three as it has a full midrange to bass body while still having a good treble sparkle. Some people call it tube amp-like, and though real tube amps come with their own distinct signatures, I think the main point with the TTVJ is that you will never feel the amp to sound digital, as Todd is a heavy analog-gear junkie and it’s quite proper that he tunes his amp to give the sound that he likes. In fact, when I did a comparison of the TTVJ Slim with the older TTVJ Portable Hybrid Tube (that uses actual tubes), I find the sound signature between the two to be very identical.

The sound of the TTVJ Slim is indeed very analog. The midrange is full bodied, without making the sound overly thick or drowning the instruments. With the TTVJ Slim, the sound remains agile and lively, as it’s able to keep up with most fast-paced rock. You get a lively presentation of the instruments through what I hear to be a slight boost on the lower treble, and it follows down with a full bodied mids and down to the bass. The bass is more focused in the upper-mid bass, and although you don’t feel it to be rolled off in the lows, the ALO Rx noticeably hits deeper bass notes than the TTVJ. The soundstage is very good and deep, though not as wide and as open sounding as the ALO Rx. If there is any complaint I have, is that the lower mids and bass section can sometime sound a bit muddy and not as well articulated as the ALO Rx. Still, given the superb overall voicing, I think it’s not going to be a big issue for most people.

ALO RX MK2 ($449)
I think amplifier choices ultimately come down to your music preference, personal taste, and the headphones that you happen to be using. I enjoy the TTVJ very much, but my friend Sem happens to choose the ALO Rx as his favorite. The very clean, grainless sound of the ALO Rx, is probably one thing that got him hooked to it. Sem is also a big fan of strong bass impact, and while the TTVJ has more of the bass in the upper-mid, the ALO delivers more low bass impact than the TTVJ. The soundstage of the ALO Rx is also wider and very open sounding, and indeed it is one of its signature sound. Personally I feel the ALO’s midrange to be too flat and not as full as the TTVJ, and this is the deal-breaker for me. But at other times, I also wish that the TTVJ can be more ALO Rx like in delivering a clean bass frequency.

Although the previous paragraph sounds like a lot of points in comparison to the TTVJ, but ultimately amplifiers are not about collecting points, and so it boils down to a synergy game. I would consider both amplifiers roughly at the same level of “sonics quality”, and the choice would boil down to the sound signature. The ALO has a lively and open soundstage, with clean highs and more impactful lows. The TTVJ has a fuller midrange, and a different emphasis in the treble than on the ALO. Both amps are very fast and dynamic sounding, though the ALO is a bit faster in pace. The TTVJ comes with an option for a built-in DAC, which makes it a fun sounding portable DAC/amp box, for roughly the same price of the ALO Rx Mk II. The DAC resolution is quite decent, but the selling point is how you get a portable amp that also doubles as a DAC/Amp simple desktop set up. I think that’s quite a deal!

Some of you may also know that ALO has currently stopped production on the original ALO Rx and is now selling the Mark II version of the Rx. Both versions have pretty much the same sound signature, and it’s safe to say that the Mark II version is a good upgrade over the original while still retaining all the good things you find on the original. For a more complete comparison, please refer to my ALO Rx Mk2 article, HERE.

HEADSTAGE ARROW ($299)
The third amplifier on this category is the even slimmer and smaller Headstage Arrow. A very, very impressive amplifier from Robert at Headstage (aka Headphonia, with a “ph”. For the record, Robert used the name before I did, and I think he deserves to be acknowledged for that fact.). The Headstage arrow is an amplifier that never fails to impress people at the first look. The super slim build and smaller footprint make the TTVJ and ALO look vastly overweight. Not only content at beating the two amps in the size category, Robert also implemented some very kickass features, some of them a first in the portable amplifier scene. The notable features are auto ON/OFF feature that turns the amp on when it detects an input signal, and automatically turns it off after one minute of inactivity (You ROCK, Robert!), automatic voltage adaptation (switches the amp between 4V and 12V depending on needs, to conserve battery life), two steps bass boost (my friend Peter is in love with the Headstage due to this switch), impedance matching switch, crossfeed switch, and three selectable gains. Robert brought all of these goodies at an incredible $299 pricetag, which directly cuts into the TTVJ ($349) and ALO Rx ($449) price.

The use of the AD8397 in the output stage is highly favored by owners of the AMB Labs Mini 3 amplifier, which naturally gives it a bit of similarity to the Mini 3′s sound. The tonal balance leans toward the “dark side” (by the way, the adjective dark is used purely to describe tonal balance, and absolutely no negative bias meant. ), similar to the RSA sound but with better presence on the upper mids. In a way the Arrow is also closer to the sound of the TTVJ, while quite different from the sound of the ALO Rx. The Arrow’s sound, is just a tad darker, mostly due to the difference in low-mid treble, where the TTVJ is more sparkly in those regions.

The treble of the Arrow is not as sparkly and not as present as on the TTVJ or the ALO, one reason why my friend Sem passed on the offer to buy a near mint Arrow at a great price, when he was offered one. If midrange and low body is important to you, but equally well you want to hear a sparkly treble, I would recommend the TTVJ sound, as it is still more lively than the Arrow. Generally the Arrow sound is quite pleasant, but the use of an analog potentiometer makes the Arrow not as good as the TTVJ or the ALO in instrument separation and articulation. Generally I would recommend the TTVJ more than the Arrow because of this factor, but if you’re considering to keep the size down while still packing serious power, then the Arrow is highly recommended as it makes the TTVJ looks rather big.

Ideally, you should base your decision primarily on the sound signature, while features and size should come second. I choose the TTVJ, but that doesn’t make it the best amp from the three. My friend Sem enjoys the ALO Rx very much, and Peter happens to be loving the Arrow a great deal lately due to the Bass boost and super-slim build. The bass boost switch is quite fun to use, as it boost bass levels up, though making the bass slightly boomier.

As I’d like to stand by that “sound signature synergy” statement, I know that in the real world, the $299 pricetag of the Arrow is a very strong point for potential buyers, and especially if you’re considering between the Arrow and the ALO Rx, which comes in at a full $150 price difference. Still, Sem is willing to dig deep into his pockets as he finds the ALO Rx to be most satisfying for him.