Tube amps - what 3 things…

Until they aren't. Tube amplifiers with output transformers, regardless of how good they are wound are not as transparent as their OTL or direct drive counterparts (given a level playing field). I've have all three design types and it's pretty clear what an output transformer adds to the mix. Getting rid of the capacitor at the output is also a benefit.

i agree with this expressed by @clio09 

witness ralph's otl amps, or my personal fave... the linear tube audio zotl40 ref+ and its remarkable clarity and palpability

no doubt output transformers do something to the sound heard out of an amp... whether that something is positive or negative is highly situational

@atmasphere

ralph, curious to know what is your take on auto biasing... now increasingly employed in high level tube amps, audio research’s newer amps for instance

the feature certainly offers a major convenience factor for users, but what do you see as the tradeoffs or downsides sonically or operationally, if any? (of course we note the obvious add’l cost and complexity of the feature)...

also, does auto biasing get the power tube biasing as precisely correct as manually biasing via multi meter (as arc used to do it for years?)

what speakers?

different tube amp qualities and features matter if you are driving hyper efficient altec horns or audio notes, less efficient harbeth monitors, reactive focals or revels, or resisitive magnepans

just like ss amps, they should be optimized to the speaker load and power/current demands

right?

op

you won't get useful answers back if you don't describe the rest of your planned system, especially speakers, room size and musical taste