Is this normal for valve amps?

[cica1066]

Yesterday I was playing at a reasonable volume ,on myrocker 30 combo with an extra pcc112 attached, when there was a sudden drop in output. Upon closer inspection the el34 on the input side was red plating. Naturaly after browning my trousers I turned it off. However when I turned it on later it was fine working as intended.
Could this be a freak event? Could something have been disloged by me stamping on a pedal? or should I replace the valves before something worse happens?

[a.hun]

Yesterday I was playing at a reasonable volume ,on myrocker 30 combo with an extra pcc112 attached, when there was a sudden drop in output. Upon closer inspection the el34 on the input side was red plating. Naturaly after browning my trousers I turned it off. However when I turned it on later it was fine working as intended.
Could this be a freak event? Could something have been disloged by me stamping on a pedal? or should I replace the valves before something worse happens?

No that is not normal for valve amps. Hard to diagnose though without seeing the amp but most likely (one of) the power valves. At any rate red plating is always a warning that something isn't healthy.

Basics: Did you have both the extension cab and internal speaker correctly hooked up to the 8 ohm outputs using proper speaker cable? Have you ever cleaned the speaker jack sockets? Worth getting a can of electrical contact cleaner and doing that. (Easy: Just spray a little on your cable jack and insert / remove it a few times as the stuff evapourates.)

If it wasn't a bad connection than the most likely thing is a failing power valve. I'd grab a new pair of EL34s or 6CA7s. That'll almost certainly see you good. If it happens again with them though it is definitey tech time.


Andy.