02-05-2017, 09:36 AM
Hi.
Totally agree with Terry. Two EL33'S is the way to go, its unlikely that Pye would have have them matched but they would have been off the same batch. Two 6V6 or 6L6 would work as well but of course the anode impedance and GM is different so output would be lower with these valves. The EL33 is a good valve and will be long lived, remember to replace any coupling and decoupling capacitors as a matter of course, the coupling caps can as you know pass DC when they get leaky which they will be which then makes the control grid more positive in relation to the cathode which in turn increases anode current, this shortens the valve's life and in an audio output stage increases the stress on the output transformer.
Totally agree with Terry. Two EL33'S is the way to go, its unlikely that Pye would have have them matched but they would have been off the same batch. Two 6V6 or 6L6 would work as well but of course the anode impedance and GM is different so output would be lower with these valves. The EL33 is a good valve and will be long lived, remember to replace any coupling and decoupling capacitors as a matter of course, the coupling caps can as you know pass DC when they get leaky which they will be which then makes the control grid more positive in relation to the cathode which in turn increases anode current, this shortens the valve's life and in an audio output stage increases the stress on the output transformer.
