Astoria Custom has sound even with master volume at 0

[Kuga]

Hello kuga,

About the power valves, the Astoria was designed for el34 (on the schematic the power valves are el34), so no trouble to install some in your amp.

The master volume is post phase inverter, cross line. A simple explanation can be that it is cancelling the sound going to each power valve. By mixing the inverted phase.

It need to be checked in the amp, but first thing come in mind is that one of the old valve is drawing less current from the phase inverter, resulting in a higher voltage on one phase, so less cancellation.

Worth to check it.

Thank you so much for the explanation.
So I undestand that some old power valves are not in good shape. In fact I wrote a mark what valves goes wrong. I won't use this old EL34 pairs anymore in any amp.

 

[neikeel]

The valves may be working perfectly well in most respects just not well matched which, as is pointed out above, will not lead to full signal cancellation with the cross line master. In other push-pull arrangements (or with individual bias pots) they may work perfectly well.

 

[Kuga]

The valves may be working perfectly well in most respects just not well matched which, as is pointed out above, will not lead to full signal cancellation with the cross line master. In other push-pull arrangements (or with individual bias pots) they may work perfectly well.

Thanks! I apreciated the explanation.