Pass Labs XA-25 vs XA-30.8 amplifier

I had the XA-25 and the X150.8 in my home at the same time for a demo. Reno hi-fi, which is gone now, but was an authorized Pass Labs dealer, graciously loaned both to me. I listened to them primarily on Martin Logan Impression 11s, and also on a pair of KEF ls50s. The XA-25 was very clean, "water clear" is the term that kept coming to my mind. The X150.8 was bigger, more fleshed out, maybe a little warmer, and more engaging on the electrostatics. Maybe because the Martin Logan's can be a little dry and overly analytical. In any case, for me it wasn't even a contest, The humble X 150.8 just sounded better and more musical. I brought the XA-25 back to Reno hi-fi and kept the X150.8. I still consider it to be the best sounding amp I ever had on the Martin Logans. And I had a lot of amps on those speakers. The folks at Reno hi fi told me they weren't surprised, and that the XA-25 was so well reviewed that a lot of customers were disappointed and several ultimately traded it in for something from the 8 series. That of course is just one man's experience (mine).

Cheers,

Ron

When I was upgrading from my Nakamichi PA-7AII (A Nelson Pass Threshold design) I was convinced I wanted dual mono's. I tried the PS Audio M700's and The Schiit Tyr (both dual mono), but while they did help with the soundstage width and depth, they clipped. Turns out my 30+ year old power hungry Accoustat 1+1 will occasionally draw a 0.5 Ohm which was not a problem for the Nak. 

I contacted Nelson Pass and sought his guidance. He directed me to the XA-25. If there was not enough power, then the 30.8 was the next option, but he felt the sonic capabilities of the XA-25 were better and would be a great match for the Acoustats. I was concerned there would not be enough power because the Accoustats have an efficiency of 82 or 83 db depending on which source if referenced. I do help the efficiency with an active SPL Crossover allowing the dual Rythmik F12SE subs handle the bass. The XA-25 handles the speakers amazingly well. The only upgrade I would make would be if a dual mono version of the XA-25 became available. Nelson's person system has a pair of XA-25 as dual monos.

Try the XA-25. If you don't like it, then go for the 30.8.

30.8 is an amazing amp with efficient speakers 

I owned both the XA-25 and XA 30.8 amps.  I preferred the sound of the XA25 - more neutral but still sweet, incredible burst, dynamics and musical element separation.  

The XA30.8 was noticeably more powerful as it should be given that it produces 160 watts / 4-ohms.  It sounded too sweet and veiled in my system, a noticeable imprint on the music.