What is the sweetest sounding tube amp.

I agree with Twl - SET is generally the way to go for maximum sweetness, as it were. 45's are sweet indeed but unrealistic for many audiophiles. 2A3's are likewise sweet but relatively skimpy on power. Both of these tubes can be simply magical on the right speakers, however.

300B's are sweet too - but have a different sound than either 2A3's or 45's, though many prefer the 300B to either.

Personally I use EL34's in a SET configuration (Papworth TVA8) and I think it's pretty darn sweet. I don't think the EL34 gets enough respect frankly. It's often thought of as a push pull tube, and admittedtly that's where it is most often used. But when run single ended it really does sound fantastic, and the word sweet definitely comes to mind!

There is some sweet sounding push pull out there, some that comes surprisingly close to SET sound.

Claud, FYI Cary used to make an EL34 push pull amp that was far sweeter than any of their current push pull and it was very close to Dennis' SET sound. Then he made a signature version that used KT88's and away went the sweetness (not surprisingly) Many audiophiles miss that amp - I am blanking on the model number, sorry!

Best,

--Evan

Cary SLA 70 Mk II - that's the model... just remembered.