Recommendation for Class-A integrated amp

Truly depends on the speaker pairing.  What are your speakers?

I did think about the Luxman L595ASE, but can't find much internal difference to justify the higher cost, so any information about the internal improvement would be very helpful.

The amp will be dual used in main system that has Abyss AB-1266 Phi TC, and the secondary system has Ascend tower with RAAL option.

Of those choices I'd lean towards the Pass or Luxman.  The Sugden would be a better fit with higher impedance speakers that aren't 25W minimum like yours.  Your Ascends drop to 4 ohms and I'd think the Pass and Luxman would cooperate very well with that.

I do lean more towards either Pass or Luxman at the moment, but also curious if there are more choices available I should be considering.

We used to sell luxman and their gear was excellent however we found the coda csib to sound even better

The coda csib is a unique integrated which is exactly the same 6300 .8 amplifier with a Coda preamp board

https://hometheaterreview.com/coda-technologies-continuum-no-8-stereo-amplifier/

The csib offers 18watts of pure class aand 160 watts class ab

You can send the amp back for rebiasing and get 250 watts class ab with 12 watts class A

You can also go to the 400 watt class ab with 8 watts class A

So you have a very flexible integrated amplifier based on the highly regarded Coda.8 amplifier

The coda throws a huge soundstage is tonally neutral has great bass and excellent clarity

Dave and Troy
AUDIO INTELLECT nj
CODA DEALERS