Portable headphone amp review

There was a pretty insane gathering of headphone buffs in San Jose today.  I was there for a few hours (it was actually my job to do setup and get people signed in for the first part of the morning), but couldn't stay long enough to hear everything.  I did accomplish one of my goals, though, which was to test all of the newest crop of portable headphone amplifiers.

For those not familiar with this kind of thing, a headphone amplifier is just an amp designed specifically to power headphones.  The earbuds and headphones that come for free with consumer electronics gear generally won't benefit from this kind of treatment, but more serious headphones are much more revealing of weakenesses in amplification circuitry, and often require a bit more juice than something like, say, an iPod is built to provide.  Amps can make a huge difference in the quality of sound you hear, and you don't have to be a freak to be able to hear differences among different amps.

You might not think this would be a big market, but headphone amps are the kind of thing that you don't need a big factory or custom tooling to make, and they present the kinds of interesting  challenges that electronics designers love solving, so there are lots of different designs, do-it-yourself projects, and one-person amp companies.

Here's the review I posted on Head-Fi :

At the meet I listened to the SR-71, Hornet, AE-1 and Coda with desktop module, with the specific goal of deciding which if any was worthwhile as an upgrade over my current portable rig.

My current main portable amp is an 8620 Pimeta, and I also have a Porta Corda II and some early Xin amps. Between the Pimeta and the PCII, I prefer the Pimeta; there's no particular thing I hear with the Pimeta that I don't hear just as well with the PCII, but over the course of a listening session, the Pimeta pleases me just a bit more.

My desktop amp is an OPA627 Pimeta, and it has a wonderful, rich, full, and fully detailed sound that I just love. Basically my goal today was to find a portable amp that matched or exceeded this desktop amp.

All of my listening impressions were on ER-4S's, which serve as my personal reference sound and which are the targets for any portable amp I buy. My main test track was Patricia Barber's Gotcha!, with some other jazz and some Marc Cohn bluesy rock as the remainder of my test repertoire.

Of those I heard today, the SR-71 simply had it: the fullness, the detail, everything. My only goosebump moments (literally, I had them) were with the SR-71. And I kept needing to come back to it to hear more.

After that, I liked the Coda/desktop. It was awfully good, and I liked the crossfeed a lot. But its sound, as good as it was, didn't quite sound "right" to me in some way I couldn't put my finger on in my few minutes of listening. It sounds good enough, though, that if I went ahead and bought it I probably would grow accustomed to its sound and over time cease to find it odd, though that of course is speculation only.

The AE-1 sounded very good, and I would say it was a step up from my Pimeta, but for me it was not a big enough step to to warrant upgrading. This was jjcha's amp (thanks for the listen!), and I had it only a minute or two, and it is of course a brand-new amp so there is every possibility that I'm not being fair to it; but at any rate that is what I heard.

The Hornet simply was not for me. I felt it had emphases here and there in the spectrum that didn't accord with the way I expected the music to sound. The sound was in no way faulty, just emphasized differently than I liked. From what Ray -- who was very generous with his time and unfailingly gracious to me throughout -- had to say, I think this amp was simply voiced with a different style of music in mind than what I listen to.

I also had a chance to hear Spektrograf's SuperMacro V3 with OPA627/stacked buffers, and I found it very, very much on par with my 8620 Pimeta. This seems an odd result given the difference in op-amps, but I believe Spektrograf heard the same thing.

Thanks very much to everyone for a great meet!  I wish I'd been able to stay longer.