Jeb, Congratulations on the new pre amp. It is really superb. I heard it for the first time today.
In an early post above, I asked if anyone had actually heard both of these in the same system. I had the chance to do a direct comparison between these two pre amps in a friend's system today. He has Wilson Sashas and a Lamm hybrid amp. We listened to both digital and analog with a variety of jazz, pop and classical. I pretty much agree with what Hornguys wrote above. These are both great preamps.
We also compared the Lamm amp to a Pass XA160.5. With both amps on both digital and vinyl, the Ayre KXR had more high frequency energy. Also, leading edges/transients were emphasized over the sustain and decay of a note. The whole sound was more forward and tipped up tonally. The Pass XP-30 was more relaxed and a bit easier to listen to. I actually found it more involving, especially with the Pass amp, but I own Pass gear, so am admittedly biased. With the XP-30, there was usually, but not always, less emphasis on the leading edge of the note but the fundamental and harmonics were glorious, especially when mated to the Pass XA160.5.
One could say the Pass pre was warmer than the Ayre, but I would actually describe the Ayre as slightly cooler than the Pass. I guess they could mean the same thing, but when viewed relative to neutral, I would describe the Ayre as beng more on the cool side of neutral than the Pass is on the warm side of neutral, but others may disagree and reverse that. Either way, it is only by a matter of a few degrees.
Both preamps are highly resolving, wonderfully functional, first rate products from very good companies. They are expensive, but offer great performance. Which preamp one prefers will probably depend most on the rest of the system and personal preferences as Hornguys suggests above.
