Ultralinear and Triode. What's the difference

To really hear what triode is all about. You need a tube amp that uses triode tubes! Pentode tubes that are in a circuit that gives the ability to switch from triode to ultalinear does not really let you hear what triode is all about! In these type amps, almost always the ultralinear mode will sound better than the triode because the pentode tube is in a circuit that makes compromises for the flexabilty.

I can give just a few cause I don't know all the tubes that are out there! Pentodes- EL 34,KT 88,6550,most pin guided sockets are pentodes or tetrodes. Triodes- 2A3,300B,45,PX 25,845,6C33,6AS7,etc. some of these have a 4 pin socket. My favorite amp is a Push/Pull 2A3 triode using 6SN7 as an input and driver tube. It's only 18 watts but, on my 91DB flat 4 ohm speakers it's plenty!

"preference in sound is 100% subjective and as such rather stupid basis for an argument" Then why argue? Your vast knowledge is impressive but, your the one that insist upon setting myself and Jeffreybehr straight. All I suggested is that I've never heard a pentode,tetrode(no matter the topolgy) sound like a true triode done class A. It's a sound preference thing that isn't worth argument. Kind of like an analog/digital, tube/solid state thing. I'm just giving my opinion to the original poster. I think that he or she may benefit from my experience. I'm going on my sound prefrenece alone, not a debate over tube topolgy correctness. Not worth an arguement!