my manual for my amp and pre-amp - both from Decware - says to roll tube V1 - 12AX7 - in the preamp and the 2 input tubes - 6922 - in the amp, before doing anything else. Amp is EL34. I currently have Winged C's and much prefer their bass and mid-range to current production from China that I have tried. Have not experimented with other EL34s or other types of tubes. My amp supports several other types, which I forget now. They are darn expensive.
Signal tube versus power tube, sound impact?
My mono block has eight KT 88 tubes(power tubes) and six smaller signal tubes. I'm using the stock tubes that came with each Mono. I think they are JJ tubes.
Rather than replace them all would it be best to change out the signal or the power tubes? Not sure how good the JJ tubes are but I hear they may not be the greatest.