Pass Labs XA-25 vs XA-30.8 amplifier

@curiousjim I bet they'd be fine for those speakers. A lot depends on the impedance curve but I used the Pass XA25 for speakers with very reasonable impedance curves at 87 and 91 db sensitivity and the amp never faltered. 

https://www.audioholics.com/loudspeaker-design/loudspeaker-sensitivity

Basically (in case you don't know): 

An audio speaker's impedance curve shows its electrical resistance across frequencies, indicating how easily an amplifier can drive it. Curve dips to low ohmic values (e.g., 2-4 ohms) demand more current from the amplifier, making it a harder load. A large phase angle (deviation from 0 degrees) at certain frequencies further stresses the amplifier by forcing it to deliver voltage and current out of sync. Speakers with significant dips and phase shifts are tougher loads, requiring more robust amplifiers.

The XA25 is designed to deliver significant current, with a peak current output of 10 amps, which translates to a 200-watt peak into a 2-ohm load. It also has, if I recall correctly, a damping factor of 500 and this gives it excellent control over the speaker's drivers, especially the bass passages.

You may want to add the coda no 8 amplifier to your list.

the coda no 8n is way more flexible the no8 can be ordered in three different variants

V3: 400 Watts x 2 into 8 Ohms

800 Watts x 2 into 4 Ohms

Class A ~8 Watts

V2: 250 Watts x 2 into 8 Ohms

500 Watts x 2 into 4 Ohms

Class A ~12 Watts

V1: 150 Watts x 2 into 8 Ohms

300 Watts x 2 into 4 Ohms

Class A ~18 Watts

"The $6,800 Coda No. 8 is very musical yet very detailed in ways that make me think that a fairer comparison would be my $13,5000 Pass Labs XA-60.8 monoblocks, which is a significant accolade for the Coda No. 8, as the Pass 60.8s are mean competitors costing far more money." - Terry London, Home Theater Review

At any time you can re-bias the amp at the factory so you can increase the amplifiers output 

Dave and Troy

audio intellect NJ

coda dealer

@curiousjim 

Nice speakers. I have Amati Traditional and power them with ARC Ref 160s in triode mode... so 70 wpc instead of the 140wpc in linear mode. They are not compromised in any way... but this is a tube amp. 

While you could probably "get away" with the small Pass. I would look up the Pass XA line up to better match with higher power. 

I purchased efficient speakers so I had flexibility with my amp purchase.

I have the XA25 running through a Khozmo preamp into the Crites speakers, which are Klipsch clones.  The amp is very pleasant and neutral.  Very good bass. Build quality superb. I will not be selling it. The 30.8 will be warmer but a even beefier amp, it puts out over 100 Class AB. It also weighs 90 pounds which influenced my decision.  If some talks you out of Pass there is Ayre, Luxman, Sugden and Coda which all have generous Class A output.

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