Pure Class-A Amp under $2000 (USED)

+3 Schiit Aegir, I have one it drives my speakers with finesse in stereo mode. 😎

Mike

+4 on the Aegir. I have one in my main system for my 88 dB 6 ohm Ohm 1000 speakers and it easily goes to my loudest needed volume (about 85 dB average) without strain. (Full disclosure, I also use a sub.)  And, I love the sound -- previously had a Bel Canto amp and then a VTV Hypex that were both higher wattage but didn't sound as good. 

Schiit offers a 15 days trial with a 5% restocking fee if you try and don't like. $40 to try it out (plus returning shipping) which is a pretty good deal. And, there is also a solid used market for Schiit gear -- you can use it for a year or two and not be out all that much if you choose later to move on.

There’s a minty looking Krell KSA 200 on Audiomart @ $2100

The Sonus Faber would like power, especially if you play loud.  Most Class A amps are small 30 W or less.  I had a Schitt.  Sounded good but not enough grunt.  You need an amp with some weight, a big transformer, etc.

There are several AB amps that would sound quite nice. Parasound, Anthem, etc.  Look on here or other places you will be set.  

PS.  I personally will always own a class A amp but high efficiency speakers make it easier.

If you’re fortunate to find a used Clayton Audio S50 while your radar is up I’d say consider yourself hugely lucky and that you jump on it ASAP.  50 and 100Wpc of sweet-sounding and pure Class-A power into 8 and 4Ohms, respectively.  Read the reviews of Clayton amps and I think you’ll find them quite special too.  Best of luck in your search!

https://www.usaudiomart.com/details/649787192-clayton-audio-s50-class-a-amplifier/