Pre-amp suggestions for Thiel 2.4/Pass Labs XA30.5

Here's a quote from Nelson Pass from a discussion about choosing a Pass amplifier for the 2.4s...

"The XA30.5 will beat out the X250.5 for the first 20 watts or so because it has a much higher bias, and this is particularly true of low impedance loads. (I used Thiel 3.6's to voice the original Aleph 0, and they were 2 ohms across the board). I suggest you take a look at the article Leaving Class A posted at Pass Laboratories which discusses this in detail."

(from: http://www.diyaudio.com/forums/pass-labs/175913-pass-labs-amp-combination-thiel-speakers-need-mr-pass-advice-everyone-5.html)

Hi all ! If it sounds good at lower volumes and gets worse at higher volume change amps . If it doesnt sound right to you at any volume (with the preamp in the system), change the preamp. The Cary slp-03 is killer for $2500 new / $1500 used , a true gem with nos tubes .

Cal3713, I don't read that as Nelson Pass specifically recommending the XA30.5 over the rest of the comparably priced Pass line for the Thiel 2.4's, only as a recommendation below 20 Watts. Seems like a highly qualified recommendation for a speaker that's manufacturer recommends a minimum of 100 Watts. I will grant you that the XA30.5 does seem to behave more like a very high biased 100 Watt "double down" Class AB amp, than a 30 Watt limited pure Class A amp. Perhaps capable of 75 Watts of Class A power into 3 Ohms before sliding into another 225 Watts of Class B power into 3 Ohms? On the other hand, I'll hazard a guess that the X250.5 is probably biased in such a manner as to be able to produce about 18 Class A Watts into 3 Ohms before sliding into about 730 Class B Watts into 3 Ohms? If you have a smaller room and/or don't listen very loud, the XA30.5 could very well work very well for you.

Unsound: This doesn't really matter, and I don't know the true state of affairs because I haven't directly compared the XA30.5 to the X250.5, but if you take a look at the entire thread, you'll see that it is actually a recommendation, and that the thread owner A/Bs the two amps on his 2.4s and vastly prefers the XA30.5. And in my listening, I'm in class A about 90-95% of the time.

In any case, this thread hasn't really addressed my actual issue. Regardless of people's perceptions regarding powering the Thiels with a 30 watt amplifier, removing the Classe from the system and using my PS Audio PWD as a preamp allows me to hear significantly more detail from my source components... so some successful preamp pairing suggestions would still be useful.

By the way, thanks for the folks that did offer some pre-amp suggestions...