As my wife will tell you, at just about every major audio show I attend I buy something (shocker right?). There’s something cool about looking at my pieces of gear and thinking about the show where I got them. For example my Noble K10’s make me think of Denver and RMAF/CanJam and working feverously with the Head-Fi crew to build all the banners before the show started (good times Joe, Jim, Jude, Warren, and Andres!). SoCal this year was about finding the best portable amp for my wonderful Kaisers, and I think I tried almost every one out there. When I worked it down to the two finalists I was wondering how to best do the final A/B comparison. I got Ken Ball’s attention at the ALO table and asked him if it would be okay if I wandered off with one of his new Rx amps for a while. He said no problem at all. Nice! (in full disclosure I did volunteer to leave my travel case containing my LCD-3’s with him as collateral, so it was very low risk to him!). However, I think that Ken might have even let me even without leaving him ~$2K in gear – he’s just a good guy. Off I went to the other amp manufacturer’s table, and many swaps of amps later I had a winner. I wandered back to the ALO table and told Ken his Rx had won the portable IEM-amp cage-match against the also very good Oppo HA-2. “Great” he told me, “and thanks for supporting Portland!”. So what won me over and what do I think of the ALO Rx? This is a review, so that’s what comes next. Geeze, why ask such a silly question…
So Ken’s ALO Rx is clearly not a Swiss-Army type of amp, this baby is purpose-built, and what it does it is awesome at. This amp is no decathlete, it’s a one-trick pony. “My name is ALO Rx and I’m an portable headphone amplifier for IEMs and that’s all I have to say about that.” Stand proud my friend, for you do your duty and you do it well.
In fact I realized that the portable amps I had been using before had bells and whistles I didn’t need and wasn’t using, and that was okay, but they made the amps bigger and meant I was paying for stuff I wasn’t using. Built in DAC? Nope, that’s part of my DAP’s duty. Ability to change gain ranges? Sorry, my K10’s are my CIEM’s for travel (and everything else currently) and when I’m home my LCD-3’s have their own dedicated amp and the Rx has just the right gain for my CIEMs. Adjustable treble/bass/etc.? Not needed – the combo of the K10’s and Rx is just the blend I need for the sound I like. Balanced output? Well, that would actually be cool, but hey, that’s outside the remit for this value-packed, option-light amp. Ability to make me an extra-hot skim latte? Hey, that’s why by law we have Starbuck’s every two blocks!
Also the Rx is lightweight, but not in a cheap way. This is custom milled metal people. For those of us who have fallen in love with titanium (my bottle opener on my keychain is titanium – guess that isn’t what the material scientists were thinking about when they developed that alloy) know that Ti is super light, but not cheap. It’s light on purpose – same with the Rx, although it’s not made of titanium, but nickel-coated aluminum (and now is available in black anodized as well). Actually the ALO Rx is like a sports car that has ripped out all the excess weight to help it go faster. This is a stripped-down, purpose-built IEM amplification machine. Don’t ask it to make you a latte or shine your shoes (wait, didn’t I already use the latte line? That’s a lot of latte). It doesn’t slice or dice, it amplifies, and it does it wonderfully – the best of any portable amp I’ve heard to date. Size-wise it’s almost a perfect match to my Fiio X3. The Rx is about ¼” shorter (when you include the volume knob) and essentially the same width and depth. A few straps/rubber bands and a nice patch cord (ALO of course!) and you’re good to go. Since I just mentioned the volume knob it’s the right time to tell you that I find it to be one of the best implementations of volume control on a portable piece of gear I’ve ever used. It’s conductive plastic potentiometer has a great range of motion and is both smooth to turn, with no degradation of the music during adjustments, and is firm enough to not get turned inadvertently during normal use. Ever almost blown out your ear-drums when you bump against a volume knob? No worries on that with the Rx in my experience.
One very cool thing is that Ken picked an orange LED to show the amp is powered on. Why is that cool? It’s not Halloween after all. Well, with the drilled grills on the sides of the amp the LED gives off a nice warm orange light, making you think of the glow of a tube, which is a theme of Ken’s work and reminds you of his other new portable, the Continental Dual Mono (which is an awesome piece of gear in itself). Was this done on purpose? I’m not sure – but it looks really cool (warm actually). The ALO Rx is made in the USA and looks hand assembled (because it is!) - almost bespoke.
Okay, so what does it sound like? Well, like most reviews I waited until near the end to talk about that (why do we all do this? Are we afraid that people won’t keep reading our lame prose and stupid coffee jokes?). The Rx has a deeply engaging sound and offers amazing resolution and decay that goes places I didn’t know a portable setup could go. One of the great things about my current reference desktop amp (the Bakoon HPA-21) is its ability to pull apart the finest details, seemingly let you identify not only the type of guitar being played, but possibly even the manufacturer of the guitar! The Rx is similar, in letting you hear great levels of detail and in a way that doesn’t distract from your overall listening experience. One example of the ALO Rx’s ability to show the texture of the notes is in the bass line in the intro to Hotel California. The Rx shows a great level of detail and emotion in these low notes while not taking away anything from the detail of the plucking of the guitar strings being played at the same time. The more you zoom in the more details you can see as you focus on a specific part of the music. This reminds me of the Sydney Opera House, but not because of that venue’s great acoustics, but rather the fact that what looks like smooth white sails on the external surface of the incredibly designed building are in reality millions of small white tiles. Pay attention in life and it’s amazing the additional things you can see and hear.
The amp is also voiced in a way that I really like. What is that voicing? I would call it neutral, with maybe a slight tick towards warm. What does that mean? Well, describing this stuff is always the hardest part. Let’s say I love the K10’s, I love the Bakoon HPA-21 and I worship my LCD-3F’s – none of which are analytical, but are a bit warm and skewed a bit towards the lower end (IMHO). The Rx doesn’t add much, if anything on its own, but allows this sound signature to shine through. And speaking of not adding anything, this amp is like a black-hole in terms of background noise – it’s just black, which is one of the reasons it is able to resolve fine details so well.
As far as the other bits go, everything works as it should. The battery is great and I’ve never run it all the way down, although I am a stickler on charging it between trips. The plugs are solid and well built, the unit itself is very well constructed and has given me no issues at all. As a bonus you even get an ALO Green Line micro USB cable with the nickel version of the Rx, which is quite a deal seeing that this cable’s retail price is about half of the total cost of the Rx. No cheap after-thought cable here my friends.
So what’s the downside of Mr. Ball’s little Rx-reboot wonder? Well, as mentioned before it is only optimized for this one use, so don’t expect it to do more. Also be sure to ensure that the range of amplification fits your IEM’s well. It should most, but there is a chance it might not be quite powerful enough for some, depending on how loud you want to listen. For example on my K10’s the Rx powers them perfectly in the range I normally listen to, but if I really wanted to blow my eardrums out the Rx won’t go that high. Actually, this is a kind a safety mechanism for me, protecting me from hurting my hearing by playing at stupid-high levels of volume. That’s the only thing I can say about the Rx that isn’t totally positive, and it actually is not a downside for me. Ken’s done a great job on this unit.
Okay, I don’t usually go for the cheap humor (“that’s not true!” you’re likely shouting) and I’ve bit my tongue to not say it until this point, but the ALO Rx is just what the doctor ordered for this audiophile who has it bad for great sound while on the go. At the list price this is an awesome deal – at the show discount it was a no-brainer. Highly recommended and my current portable reference.
I can say the jacks we use are very robust Switchcraft jacks and will not fail and they are secure to the PCB. I do not anticipate any issues with them,
Ken