Question about Class A

@jay73 You can find a used Parasound A21+ for around $2500. Which is what I paid for it. I traded it in for a KRELL 175XD but the A21+ was very good.

[edit] Oops. I did not realize you were referring to the Sudgen . However, have a listen to the Parasound. It is rather good and in the price range you seek. The first 6 watts are Class A.

Forget anything about marketing and of course Krell 175 doesn’t have 175 Watt Class A, even most of Pass Labs amps don’t. Normally you will have 20-30W Class A, producing a heat of more than 100-150W for that kind of power. I doubt there is a good cheap Pure Class A out there, because design, materials and heat dissipation will make it heavy and expensive.

Here is the marketing for the KRELL. iBias Technology – Krell (krellhifi.com)

Krell’s iBias Class A technology allows our latest amplifiers to run in full Class A mode to full power while minimizing heat generation. Previous efforts at using a “tracking” bias, while effective, only measured the incoming signal and set bias levels from this information. Our new patent pending iBias technology significantly elevates the effectiveness of previous designs by calculating bias from the output stage. This seemingly small change in topology results in a dramatic improvement in sound quality, especially midrange richness and purity.

Seems pretty clear to me.

I have to second the Krell K 300i with it’s Patent Pending I bias circuitry -  I have owned my Krell integrated for over two years and drive Maggie 1.7is. It fills the room with Class A sound and never runs hot. New it does cost $7,000 but if you find one used grab it - you will not be disappointed - build quality is amazing!

I’m using Pass Labs XA30.8 with Martin Logan Montis. Preamp is Pass XP-12. 
Incredible sound and never runs out of headroom no matter how hard I push it. 
Purity, dynamics and details in spades. 
I wouldn’t hesitate going with Pass Labs amplifiers. 

@yyzsantabarbara , you mentioned Parasound. I was actually thinking about Parasound also but maybe the A23+. If the A21+ puts out 6 watts in Class A then the A23+ might be half that or something, I am not sure.

But I suppose it could still sound good. Overall seems to get good reviews. 

The one thing I am confused about these types of amps is, at what point or volume, does it switch to AB from A.

With the Parasound, if I listen in low volumes, am I pretty much staying within Class A territory?

The Krell, as I said before, might be out of my budget but I will keep a eye out. But I have to say one thing (don't hate me for it, haha) but at least from the pics, the aesthetics do not look that attractive). I know, I shouldn't go on looks but performance.

The Nelson Pass First Watts might be an option to.

Damn, so many good choices. 

@rfnoise. +10

Great advise given thus far.  That Coda is a bargain.    Excellent amp, excellent service.   I have a Coda S-100 and won't part with it...  I also have Mephisto Solos,  Boulder 2050/2060 and Krell KAS amps.

Give the Coda a chance,  you won't regret it. 

Good luck in your search, 

Jose