"Count Floyd" wrote in message
news:BJ4mQCBKg9HM-pn2-3dWudjBJPujT@localhost...
Just changed some tubes in my S-38 and the original 50L6GT was changed
to 30L6GT by my tube supplier. I know that it is the audio output
tube, but listening to it does not seem to make any difference. Is
there a difference? Should I pull the tube and use the 50?
Thanks
--

Add up the tube filament voltages and see which tube is closest
to what your line voltage. I'd think that the 50L6 would be
preferable.