The International+ by ALO Audio

Sound Quality

The International+ is also not the quietest amplifier with regard to hiss and becomes a problem in high gain mode, especially so with the use of my custom JH16 Pro iems, Cleartunes CT200 and a few hanging style ear buds that I own that are known to react poorly to noise. With each flip of the switch, you can gear a marginal increase in static in the backdrop of the music or track being played…upsetting to say the least. Its not a dead silent amplifier, although when used as a source in Dac mode it is very quiet indeed with noticeably less static makings its way through each gain mode function.

An odd thing I found, which may be a glitch or something is that when bridging the International+ to a portable sources 3.5mm output, to the amplifiers 3.5mm input, the portable source will still play normally despite the Dac mode switch enabled. I would never do this knowingly, but I noticed my portable source was playing through the amp while the switch was pointing towards the Dac! Toggling the switch back to the portable source side doesn’t change anything continues to play normally. This is really odd, sometimes you can hear very low volume on your track if you accidentally flip the switch to the Dac mode on portable amplifiers, however this time the experience is lively, full and normal in every way. I am not sure what to think about that. I would certainly prefer the portable experience to stay portable when that mode is selected, I would want it to automatically be muted or shut off if I accidentally flipped the switch from portable to Dac mode. Yikes. Thankfully, this doesn’t occur when I bridge my portable source’s 3.5mm output to the Internationals balanced 4pin input. No sound is emitted when the Dac mode is selected, but the source portable player is active through this type of connection. Weird.


I think the ALO’s portable amplifiers best qualities reside in their treble experiences, which tend to be a bit brighter and more airy, lively and colored to my ears. I don’t really hear much of a clarity difference between the original International and this new + version, however I do find that my iems are naturally fuller and more well driven by a slight degree over the original International that I’ve owned for some time. This difference is most apparent in my JH16 Pro, the 1ohm revision in the new International+ seems to play nicer with the customs iems I own, forcing them to sound less thin and noticeably more bloomed ( in a good way ) on the low end. As I hear it, the bass qualities on the International models are not as good as the ALO MK3 models, which is a pure amplifier without a dac that costs $650. It is also an amp that I feel to rival the RSA SR71B and even best it on the treble and overall separation qualities, however one that I also find personally to be inferior to the RSA F-35 Lightning and SR71B in background noise, hiss and overall bass yumminess that the F-35 has in abundance.

I consider the bass mildly impacting, I would never call this amplifier effortless or reserved, nor would I call it overly punchy and with too much kick. Overall clarity is not as clean nor as pure as my RSA F-35, but considering the International+ is able to be used as a dac as well as portable amplifier, I really cannot say anything negative. I don’t think purists would want this amplifier and should stray away from it, as I find the overall coloration of the low end to portray something a bit softer on the edges, but with a firm solidity. Reminds me a lot of the Beyer T1 and how it portrays bass. It is a shame the T1 is too inefficient to be powered nicely by the International+. Even at lower volume, the T1 still is very apparently well paired with the International with regard to sonic qualities, this would be a really great meshing if the International+ were more powerful.

The midrange of this amplifier is thankfully not recessed, nor overly forward. I think the F-35 is certainly more engaging, and other amplifiers like the TTVJ Slim and Apex Glacier are slightly artificial sounding in the vocal experiences, all be it they are both more spacious sounding by a noticeable degree. Due to not offering what I would consider a very forward sound signature in terms of physical layout of the sonic experience, I cannot recommend the International+ as a vividly engaging vocalists amplifier, nor something suited for those who like an intimate sound. This is a middle ground sound type that plays it safe in attempt to perform admirably in most areas. I personally find it quite boring in the physical locale of the sonic presentation, neither forward nor too recessed with nothing really reaching out and grasping you. Some portable amps I’ve owned have some great defining feature that keeps your ears interested, especially so when you swap between other models and realize the jump you’ve made portrays something lacking to your ears, thus making you want to revert back to the model you were using prior. I can’t say I’ve experienced that at all with the International+ because it is just so generically tuned and setup. If I had to short guess what my favorite quality offered would be, it is certainly the treble which I find more enjoyable than my RSA F-35 for example, which has a darker house sound, but also one that is more pure, forward and engaging. I don’t think the International+ is going to take my away from my beloved F-35 but I can surely say that there are a great deal of audio enthusiasts with opposing tone preferences to mine, users that would naturally enjoy the more middle ground experience and brightness on the upper end that the International+ offers.


Crazy Rig Pairings

Watch The Duck – Reactivated

I’ve selected this track not only because I enjoy it, but also because it offers a good sense of low end and treble-ish goodness in the Dubstep genre. I wanted to test PRAT and slam factor on the low end between balanced and unbalanced rigs. It is very evident that the Treble and midrange experience on this dac/amp is good and also that it didn’t shift too much from rig to rig, however the bass experience did.

Foobar2000 via Dac Wasapi output
Flat EQ/Disabled
Bauer Stereophonic Binaural DSP active : J. Meier setting
RealBass Exciter DSP Active : See Image below for complete settings
JH16 Pro with stock 3.5mm cable


The bass effect feels a bit thin, watery and loose with some soft edges by comparison to what I know this Dac sounds like with the JH16 in balanced setups. I don’t find the experience to be solidly weighted, although I feel the clarity is perfectly acceptable. While not screaming amazing clarity or style, the International+ in unbalanced mode via a portable devices 3.5mm output seems more than capable enough. I do find that solidity factor a serious issue when comparing the same track and rig pairing in a balanced setup though.

Foobar2000 via Dac Wasapi output with all DSP settings untouched from the unbalanced test
ALO International+
JH16 Pro with Artemis Cables custom 4pin Hirose ALO/RSA balanced cable.

Instantly apparent what the true balanced rig can do for the JH16. With all settings left unaltered from the previous test and swapping the stock unbalanced cable for a custom balanced cable, the low end experience is something I would expect of a better Hifi experience. That soft edge work is gone, wiped clean and replaced with solidity that I desire. A more weighted sound signature on the low end for sure, but sadly still not as clean as some of the more higher end pairings I’ve tested. This is still only in the acceptable range for clarity all around, something I would use as a stepping stone with higher end monitors or headphones to a better dac, or something I would surely use on the go with a laptop but never as a primary rig. I’m a snob and am hard to win over with my JH16.

Via the Astell and Kern RWAK120’s 3.5mm output ( Red Wine modded AK120 )
International+ 3.5mm input
JH16 stock 3.5mm cable
A custom copper 3.5mm to 3.5mm cable I built years ago for myself

I feel the general sound signature here to be unsatisfactory, the International+ is unsuitable for primary usage with the RWAK120 as I feel their sound signatures to differ too extensively. They do not pair well in my opinion and the International+ is a clear bottleneck for the sound quality offered through just the RWAK120 alone. Swapping between the RWAK120 with the stock JH16 cable and the experience is pretty darn good to me, something I’ve been using for quite some time and am very used to, so I do admit a little bias to the sound signature preference and pairing these two make, but it is very obvious that bridging the RWAK120 to the International+ via the 3.5mm input, and then using the JH16 on the Internationals 3.5mm output results in an inferior overall clarity experience from just using the JH16 with the RWAK120 by itself. That bass slam and solidity is severely lacking and does not do the JH16 justice in the slightest.

I feel crazy right now, so lets really get weird. Oh yea. Lets see what happens when we combine the ALO International, the F-35 Lightning from Ray Samuels and a few other headphones with this track. This should be fun!


Via the Sansa Clip Sport 3.5mm output → ALO International+ 3.5mm Input > 3.5mm Output
Disabled EQ
JH16/AKG K812/MrSpeakers/ Alpha Dog/ Audeze XC

JH16: Flat bass response, but surprisingly cleaned up over just using the Sansa Clip Sport alone. Watery, loose, flimsy bass impact.

K812: Not bad actually, the K812 seems to play very nicely with this pairing, oddly enough. Plenty of bass kick on high gain. Of course, it isn’t nearly as clean as it should be, but in terms of physicality and quantity the experience isn’t half bad. I get could by on this and use it for lounging around the house or outside.

MrSpeakers Alpha Dog: Bass anemic, nowhere near enough juice to get the job done.

XC: Hmm, this turned out better than I thought it would. The XC doesn’t really have as much kick or quantity as the JH16 or the K812, so it fairs a bit better here on this rig. Of course, still not “Hifi” enough for me in overall clarity. Muddiness is audible but the general weightiness isn’t that much different from only using the RWAK120.

Via the Sansa Clip Sport 3.5mm output → ALO International+ 3.5mm Input → RSA F-35 3.5mm input → RSA Balanced Output

OK, this is odd, who would do this anyway on a portable rig? Nobody, that’s who. I found it giggle worthy to see where this would lead me. The International+ is again the bottleneck for the experience, as it is noticeably cleaner when using the Clip bridged with the F-35 with all of the headphones I own that are balanced. I assume the same would be said for the K812, which I don’t have a balanced cable for. Clarity is inferior when the International+ is last in line and when the F-35 is outing its signal to the International+. The reverse, where the International+ feeds the F-35, is more clear due to the RSA F-35’s very obvious sonic clarity superiority. The entire experience both ways is muddied by the International+ and the Clip, but I wanted to test this rig because the Clip Sport is improved in sound quality over the older generation Clips, which I’d found to be very fun to use. The pairing with the International+ and the clip alone, then outed to which ever headphone is actually a solid improvement in clarity and staging over just using the Clip alone, so this was certainly worth it to bridge these two together.


The same cannot be said when bridging my RWAK120 to the International+, the experience everywhere is a noticeable downgrade over just using the RWAK120 by itself with each headphone. The sound quality of the RWAK120 ( which is damned expensive at nearly $1600 total ) is much better to my ears. Smoother, more refined, more detailed and with a better stage depth than when the ALO International+ is part of that pairing. No surprise to me that the RWAK120 and the F-35 pairing is more clear and tonally focused throughout than the International+ is, yet it is still inferior to just using the RWAK120 by itself. The only reason I use the RWAK120 with the F-35 is for use with my Alpha Dog or a number of other balanced headphones that require more voltage than what the RWAK120 can spit out on its own.

Now, here is where things got interesting. When using the ALO International+ as a Dac, connected to the F-35 in a legit balanced setup with an ALO balanced to balanced interconnect ( The International+ as the dac, the F-35 as the amp ) the experience is very good. That bass weight solidity flows freely, especially with the Alpha Dog and JH16 as the F-35 cleans up the signal from the Internationals sourcing of Foobar2000. This is a good pairing for a number of reasons. The most prevalent is that tone of the Internationals treble, which pushes it way through into the F-35 a bit, thus making the darker upper end of the F-35 more enjoyable. Another reason is the physical footprint of the rig, its damned tiny and invokes a nice sense of space on my desk. This is a rig I would use as a primary home or college dorm room setup if need be. If I didn’t own my Oppo HA-1, which is both a dac and an amplifier that costs $1100, I would certainly consider this ALO International+ as a Dac and the F-35 bridged to it at all times for home use with the middle tier headphones I own. As far as balanced rigs go in this price range, this is very nice.

Click here for final thoughts…

Sharing is caring!