300B or 2a3 SET Class A for Heretic Model A?

It has been a while, but, I have heard the Atmasphere M 60 and M 30 amps.  I liked the sound a lot--very alive and vivid without being harsh.  If you are looking for extra warmth, they might not be ideal, but, they are still very fun to listen to.  More recently (about three months ago) I got to hear their MA 2 (I believe) amp which is much bigger and it sounded great.  Some SET amps are also very lively and dynamic sounding within their restricted output, but, OTLs do the extreme dynamics too and should certainly be under consideration for a tube-based system.

we are a Mastersound dealer the compact 845 is a remarkable amplifier reliable, dynamic, with enough power to drive more moderately efficient set of loudspeakers 

one of the most memorable amplifiers I have ever owned in 40 years of professional system design.

Dave and Troy

Audio intellect NJ

Mastersound dealer

Another plug for Aric. I've owned three of his amps and was elated with each one of them. I just sold my Super 300B and I will miss it dearly. It just didn't fit with my new speakers.

Aric is the man and he won't steer you wrong.

I can recommend:

1. 300B integrated Allnic T-1500. I listened to it in Montreal Audio show and it sounds really great. It has 6sn7 driver loaded on choke - LC coupling.

2. Aric Audio Super 300B. It should be even better because it has 6v6 powerful driver tube with inter-stage transformer. That is very important for difficult to drive 300B.

3. Coincident Audio Frankenstein - mono blocks. It is also has inter-stage transformer and powerful driver tubes. I listened to this amp in my friend's system.

@alexberger I tried Coincident Frankenstein's with Altec Model 19's, thinking that the Altec's 99 dB efficiency would pair nicely, but unfortunately, the Frank's made the 19's sound under powered.   It's possible that the 19's impedance curve is demanding, as I've tried numerous amps, many of which didn't seem up to the task, as the sound was lacking in bass and dynamics.  I'm currently using McIntosh MC-30's and they are the best I've found so far.