After a couple of listening sessions, I can say without question that the Rx is a very special portable amp. I've been alternating between my Edition 8's and my Ultimate Ears UE5c to get impressions for both a full-size can and IEMs.
First off, the Rx has power, and lots of it. It drives the Edition 8's authoritatively. As anyone who has heard the Ed8's knows, the bass is very prominent in the mix, and the Ed8's IMO need proper amping to keep that bass under control. The Rx succeeds beautifully in presenting the bass as tightly and well defined as I have ever heard from the Ed8's. I have always found the midrange a bit recessed with the Ed8's but the Rx gives the mids much more susbstance and weight. Overall, the Rx seems to be able to drive full size headphones without breaking a sweat. I need to give it a real test and try it with the HD800's!
I've owned the UE5c's for years, and for those who don't know because UE doesn't actively sell this model anymore, the UE5c is a custom IEM designed during the Jerry Harvey era with a slightly tilted up bass response. They were designed as an IEM that would give a full sound with a bass presence unamped. Well, they do that, but when I listen to them unamped, I detect a real smearing of sounds. Instruments tend to blend together and get lost in the mix. The clean, crisp clarity you expect from an IEM seems to be sacrificed.
However, the Rx has given the UE5c's new life. I'm enoying them so much with the Rx I'm not sure when the Ed8's will get a listen again. The Rx really opens up the sound. The smearing is gone and the instruments are clearly separated and distinguishable. The level of detail across the spectrum is instantly noticeable. And despite the power of the Rx, the floor noise is dead silent, even with my IEMs. As a frame of reference, I've amped the UE5c's in the past with an RSA Tomahawk and while I've always enjoyed the Tomahawk's sound signature, the Rx has taken the UE5c's to another level of definition and refinement I didn't know was there. And I've had these IEMs for over 4 years! Maybe I can hold off on that JH13 purchase for awhile!
The Rx truly seems to be an amp that can handle just about any IEM, closed, or open phone you can throw at it. The build quality is first rate and the dimensions are such that it almost seems custom-made to pair with an iPhone or iPod Touch. While it is certainly larger in size than the hotly anticipated RSA Shadow or HeadAmp Pico Slim, the Rx is only a shade thicker than either of those two, so it's just as easy to slip into your pocket, especially if you are like me and you already have something the size of an iPhone right next to it. I need to post some pics of the Rx with my iPhone to illustrate how slim this amp is.
Ken at ALO Audio has done a great job with this amp, and if you are in the market to buy something in the increasingly large field of slim portable amps out there, you really should give the Rx a listen.
