Harking back to Mapman quoting Einstein... the only way to really get a handle on this is to get yourself to a show or an audio club and listen. See what floats your boat. Right now I am listening to an 18 wpc SET amp driving 97 dB high impedance speakers in a 14 x 23 x 8' room. I have to use 10 db attenuators to get the volume control up to 10:30 and it's about as loud as I ever want it. Plenty of bass. Vocals/midrange sound RIGHT. Source is 16/44.1 Pandora, so it's not the ultimate in detail, but it sounds pretty darn good to me. Go to RMAF and hear Ralph's 60 watt OTLs, driving the Audio Classic horns to near rock concert levels in one of the very big exhibition (not sleeping) rooms will show you that you do not need a mammoth amp (ss or tube)to provide mammoth sound w minimal distortion. OK, the cost is a little heat. Maybe you live in Phoenix and that is a game changer for you. That's cool (pun intended). Give a Berning ZOTL amp a try. Long tube life, auto-bias, compact, pretty cool running- certainly cooler than many ss amps biased into class A.