Thank you all for your responses. The amp is almost always set at triode mode. Only one time I ran with UL a few years back. For some reasons (if I remember it correctly) it sounder too boomy and reminded me of a solid state amp. Sometimes I think getting the V12 was a little curse since it is expensive to try out different tubes.
Cary V12R Tubes
I would like to try different tubes for V12R. Currently I have Svetlana EL34. I want to know which one of the recommended output tubes (per manual it could use either 6550, KT-66, KT-77, KT-88, KT-90, 6L6) should I try and what sonic different for each would I get?