Valve issue?

bencowling81

My Maz 18 when turned up is intermittently losing volume (not completely but I'd say at least half), then comes back in, almost like a very very slow tremolo effect. Is this common and is it likely a valve issue?

Any help much appreciated.

ecc83

When it dies next time try to check if the heaters have dimmed  you might have a bad joint some where in the filament circuit.

Dave.

ICBM

ecc83 said:

When it dies next time try to check if the heaters have dimmed  you might have a bad joint some where in the filament circuit.

This. Slow fade out and back in is a filament issue, either one valve or the whole supply. The first thing to do is check if it affects all the valves or just one.

If it’s just one, it could be as simple as a dirty contact between the valve and the socket.

bencowling81

Thank you @ecc83 and @ICBM - I’ll try to see what’s happening around the back next time it does it.