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

Cal3713...the output impedance of the Aesthetix Calypso may present a problem in the treble region given the high impedance at 20KHz (3900 ohms vs. 30Kohms input impedance for your Pass amp via balanced, < 1:10 ratio). On paper, this suggests potential attenuation (or think of it as a roll-off) in high frequencies, so this may make the overall tonal balance more shifted towards the midrange and bass. If you are set on that option, I would highly recommend trying it in your rig before purchasing if you can.

You should check the ARC LS-17 for measurements as well. If you cannot find output impedance curve, I would call ARC and ask them. Let them know what amp you have so that they can advise you on whether the LS-17 would be agood match from an impedance perspective.

Good luck.

Unsound, not I'm not, I guess I just saw in some other threads that people had used those with Pass Amps and had success... and they were recommended in here. And, perhaps it was just made it an easier choice to be biased towards either tubes or SS. You'd personally choose a solid-state? I did see that there's a Pass X1 up for about $1900.

I can see advantages for either ss or tubes, but the Pass input impedance and preferred use of balanced inputs might make for limited tube choices. I think the a Pass pre is a no brainer. Tube options include Sonic Frontiers Line 3, and though I'm less familiar with them, the Atmasphere pre's look like suitable candidates.

Thanks unsound. Despite it's auspicious start, this thread has ended up being useful, both for recommendation and educational purposes...

It isn't balanced but the extremely low output impedance is part of what sold me on the kW preamp. And its other measurements and the monster transformer didn't hurt either...