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

I think you'll get better and cheaper results if you'll just use CAP151 which will make much more sense than your current Pass that underpowers your speakers. You can order a phono board from Classe and mount it yourself with easy instructions from manual. Child skill of Lego assembly experience is sufficient enough to do that.

Unless you think the amp is underpowered all the time, meaning that the needle is always moving... then don't you touch that amp! Kidding of course, but it's a fine amp and probably stays in Class A most of the time. Look into the W4S STP-SE preamp as it's fully balanced to match well with the XA30.5 plus it has a very low output impedance that will mate well with your amp. Alas, no phono stage, but you can get one of your choice, and still come in under budget.

As mentioned above, I was also pretty concerned about the power of the amp and was set on purchasing an X-250.5 for the Thiels. I eventually settled on the XA30.5 after seeing Nelson Pass explicitly recommend it over the other comparably priced amps in the line.

So far, the amp only moves out of class A at very high volumes, higher than I would use for about 90% of my listening... and still sounds very warm and sweet even when the needle starts bouncing.

As for the problem with the Classe, it's great and I love it, but unfortunately, it's obscuring some detail from my source components. I've got a PS Audio PerfectWave DAC and there is a lot more information in the system when I use it as a preamp and run it directly into the Pass. Alas, my girlfriend loves vinyl, so that's not a solution either.

Ohh, and for those offering solutions, my $2500 cap is for used equipment. I won't buy new.

Did "...Nelson Pass explicitly recommend it over the other comparably priced amps in the line." for the Thiel CS 2.4's? Thiel suggests 100-400 Watts for the 4 Ohm nominal 3 Ohm minimum 87 dB/2.8V/m CS 2.4's.

If you're staying in Class A 90% of the time you are OK. Leaving Class A is not going to cause any harm. At 4 ohms you still have 240 watts of Class A/B headroom left when you leave Class A.

Some people feel that you need amps with a lot more power than what is required by your speakers to get the best sound. Others don't. If it sounds good to you, that's the main thing.