Larry, I certainly appreciate the explanation about
burn-in. I had not given sufficient thought to the lower voltages of these amps, and that part makes a lot of sense.
I also appreciate your comprehensive review and followup posts about the
Headsix and
Lyrix and
Caffeine amps. I've been pondering a good headphone amp for some time (for possible matching with an AKG K702 or Denon AH-D2000 --
or possibly the D5000), and with "less than $200" being my price limit, these amps seem to give a lot of performance for the Dollar.
Your reviews of the
US$185 Headsix show it to be about on part sound-wise with the
US$159 Lyrix after burn-in. Indeed, you mention that the
US$69 Caffeine gets better sound than the Lyrix in some respects. In such a case, the Caffeine would appear to be the most logical choice, at $116 less than the Headsix, unless you want to keep an amp in your front shirt pocket all day long. And while I fully understand the need to support this site financially, the Headsix is still $26 more than the Lyrix and $116 more than the Caffeine.
The amp with the most bang for the buck is without a doubt the Lyrix. For $26 less than the Headsix, despite a marginally larger chassis, you get crossfeed, bass boost and a great USB DAC! Even without the DAC, the crossfeed (and to a lesser extent, bass boost) would make me lean in the direction of the Lyrix. But the fact you get that for a lower price too makes the decision pretty easy. And so in light of this, I am quite surprised that there is such a dearth of info on the Lyrix versus all the posts and information I was able to Google up about the Headsix. Both amps have been out for a number of months now, so I would have expected to read more articles on these amps, from a diverse number of sources.