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

 I also agree with the poster who said running low powered SETs gets you entrance to a cult, and it’s one where you can land on some magical combinations of speakers and amps. 
It’s all fun, so long as you don’t mind losing your eyebrows every once in a while.

Its really about SETs being a musical instrument rather than a music reproducer. Fun, but its not at all accurate to the recording. That profound ever-lovin' 2nd harmonic gets a richness that isn't part of the original recording; that is why I say 'musical instrument'.

@alexberger my room is not small @ 14' x 26' x 7.5' tall with a 6' wide opening that leads to an adjacent room.   My Altec's use Werner Jagusch crossovers, so it's possible they are contributing to inefficiency or negatively impacting the impedance curve, more so than the original stock crossovers, but I can only speculate.  In addition to the Franks, I tried an Elekit 300B amp and it too struggled to drive the 19's.  I did try a Line Magnetic 845 based SET integrated... and while it did sound fantastic in many respects, it emitted loud buzzing sounds from both the speakers and eventually the transformers... so as much as I would have loved that combo to work, the buzzing and transformer noise was a show stopper.  I'd like to try another 845 SET amp with the 19's again down the road... thinking Mastersound Compact 845, deHavilland Aries or Audion Shadows.

@pdreher Keep an eye open for an Art Audio Carissa. 845 SET and a great match with vintage Altec.

PS- I ran Valencias with Model 19 crossovers for a while and those things benefited from some juice. 

@rooze I love the sound of my McIntosh MC30's, but always have an eye out for reputable high quality 845 amps/integrateds to have as an alternate that I can swap with the Mac's for a different flavor.

“It’s really about SETs being a musical instrument rather than a music reproducer. Fun, but it’s not at all accurate to the recording. That profound ever-lovin' 2nd harmonic gets a richness that isn't part of the original recording; that is why I say 'musical instrument'.”
 

To me this is also a specious point, the idea of accuracy in recorded reproduction. I’m looking for something I  like. I don’t want a stereo limited by only sounding good with any particular music or record label. It’s not about accuracy, to me accuracy is anti musical. I want the music I listen to- to be engaging. Accurate is irrelevant, in fact I don’t think it exists. Perhaps an extreme view point. You get into set amps because you want to experience the music not judge the recording.