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

@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.

@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.

@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.