ALO Audio Rx
Headfonics 2015

ALO Audio Rx Review

The ALO Audio Rx is a second-generation single-ended portable solid-state amplifier, noted for its expansive soundstaging properties. It is priced at $349.

Disclaimer: The ALO Audio Rx was sent to us in exchange for our honest opinion in this review. We thank ALO Audio for this opportunity.

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ALO Audio Rx
However, if you are an IEM guy, got a midrange DAP and want a little more juice to really liven up those IEM's without any unwanted noise or hum then the RX is probably going to get my vote for one of the IEM analog amps of the year.
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In late 2014 I emailed ALO asking them what is the game plan for 2014/2015 and they had a few ideas in the pot but otherwise, I felt they had a fairly quiet year in terms of big-ticket releases. The fact they didn’t have a table at CES2015 actually got me a little worried that perhaps the ALO Audio juggernaut had ground to halt a little.

Yup we had some nice revisions of the National and the International but nothing seismic or show-stopping. Glad to say with the release of the reinvented RX IEM amp over the last few weeks that is not the case at all.

The revamped tube amp/DAC Continental may have stolen the show at CanJam 2015 SoCal but at $299 (promo price) and standard SRP $349, the RX portable amp might just hit the sweet spot for a ton of IEM users out there searching for something a little special and blissfully noise-free.

Yes, it’s an oldie, their first-ever amp was indeed the RX amp, but the thinking on this one is all new.

The RX Line

For those of you who have been into portable amps for more than a few years or tracking the rise of ALO Audio will know that before they adopted their neo-retro geographical/travel style branding of the last few years they actually started out with the RX brand which is still with us to this day.

The original, of course, was the iconic RX (mk1 shall we say?) and then the RX2 around 2010 followed by the RX MK3 (multiple versions) that they sell right up until today.


My first actual exposure to ALO’s fabby range of amps started with the RX2 in September 2011 when I was stacking with Cypher Labs SOLO DAC back in the day when bypassing an Apple DAC was something unique and stand out rather than the standard you find today in many amp manufacturers.

The RX2 was the perfect physical form factor and match for the SOLO at the time, sporting a jog dial for volume much like the original, a hi/lo gain option and was a considerable size increase on the original RX portable amp partly due to the need to match the SOLO form factor for stacking purposes.


The RX MK3 went even bigger and opted for power and balanced to the detriment of IEM users because the one thing that really the RX series didn’t really cater for was the IEM crowd. The RX3, while seriously good for the planar crowd was, and still is, a bit of a noisy chap when it comes to highly sensitive Earphones.

The RX range started out with the powerful RX amp but increasingly becoming all about power and headphones. Well fast forward to 2015 and the big money is now on a revitalized DAP market and ever-rising custom monitor usages (and prices!).

That market is all about sensitivity, low to zero noise floors, low impedance output and something very pocketable. If you are going to do an analog portable amp these days you have to bring something special to the table because convergence DAC/AMPs like Oppo’s $299 HA-2 does a hell of a lot for the price.

Modern Retro

ALO has responded to that market challenge by reintroducing the new RX as an analog amp geared to IEM users and out of the little black retail box, it is clear that portability with a modern take is high on the list of features for this new iteration.

The form factor is classical portable amping in its lines producing a very familiar feel to its handling and stacking capability. Measuring in at a very tidy 2.28×3.64×0.69 inches in diameter and plated with a very retro looking and stylish nickel-plated CNC’d aluminum enclosure the RX is a very striking diminutive portable amp.

Now you may notice in the pics that nickel plating looks like it has pulled through a bush backward giving it a rather fetching worn look out of the box. Speaking with the guys at ALO it would seem that the Nickel plating can show up oxidization fairly easily along with smudges and smears.

Personally I think it is just dandy looking but if you want a perfect look to the casing then simply apply a bit of vinegar and it will look fresh as a daisy thereafter. Otherwise, leave it alone, the worn look is perfect.



Both sides of the RX have an array of venting holes for heat dissipation. They also produce a nice little orange glow from the LED orange power-on indicator located at the front of the amp or a similar LED light at the back which turns on when charging.


To carry the RX portable amp ALO has kindly included a small padded cloth type pouch with a netted design and accented with an ALO Audio label on the side and a drawstring at the top for safekeeping when the amp is inside.

Along with the pouch, the RX comes with the usual ALO Audio branded straps for stacking and a USB socket 5v AC charger and a lush Green Line USB Cable.

The Plastic Pot

To the front of the RX ALO has done away with any fancy gain circuitry and gone straight for a simple analog line in and headphone jack out in 3.5mm format with a silver-coated metal ALO knob over a plastic element type potentiometer.

The plastic potentiometer is a deliberate move by ALO away from carbon-based variants which tend to have a shorter life span and. The reliability of the plastic is also normally preferred to the carbon-based variants given they are traditionally a bit quieter than hot-formed carbon when in use.

Carbon tracks wear and tear fast and often in a very uneven manner leading to scratching and long term channel imbalance. Precisely the very issues this new RX wants to avoid if it is going to appeal to IEM users.

DSC00101The Green Line

To the back you have a touch of the modern with a micro USB charging port (5V DC from USB bus) and an orange LED light which turns on when connected to either your PC or the accompanying USB charger and cable and then green when charged.

This is a bit of a change from the normal 9 or 12v AC charging circuitry they had in previous units such as the RX range and the National/Continental type units and more in line with their smaller Island DAC/AMP which was also USB charged.

Thank god for that actually since am I already coming down with a ton of chargers that I constantly need to label to prevent unwelcome voltage related accidents. You also get that nifty Green Line branded micro USB cable that when I checked ALO Audio’s online store sells for a whopping $149.

That just makes this the second most expensive USB cable after the Kingrex splitter in my collection. Handsome USB cables are always a welcome edition and this one is no exception with a solid green sheath and gold plated micro and USB A connectors.

Click On Page 2 below for Sound Impressions & Comparisons

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