Telescopic_trade, have you gone over to Bill Baker's website (response Audio)? He does a LOT of modification work on JoLida tube-only amps (i.e. NO hybrids) & he does have several tube recommendations that are HIS favourite. Try one of those. Here is the website addr for tube recommendations. There's a lot more on this site.
http://www.responseaudio.com/recommended_tubes.htm
On my 502A I have the winged-C Svetlana 6550, which are #3 on his list (of 3!! ;-) ).
So far, so good for me.
http://www.responseaudio.com/recommended_tubes.htm
On my 502A I have the winged-C Svetlana 6550, which are #3 on his list (of 3!! ;-) ).
So far, so good for me.