Rocker 30C giving up the ghost...

[tarfungo]

...more specifically, low frequencies...

Hello All!

While at rehearsal last night, my Rocker30C would intermittently go into a hyper treble sound mode as if a high pass filter was being applied - losing most of it's bass frequencies and also becoming somewhat more distorted (natural channel in this case) compared to the 'normal' sound. This would last from a few seconds to a few minutes, then back to normal.

This affects both channels, with or without pedal board and after swapping guitar cables. I tapped around on the tubes while it was in its diminished state with no effect.

Tubes are about 6 months old (full re-tube), NOS bought from an Orange Forum recommended 'good guy' tube dealer. I have the old set of tubes I could swap out as a troubleshooting step, but I was wondering if anyone had any more specific thoughts about what might be going on?

Thanks in advance for any thoughts...

[a.hun]

Not guaranteed, but quite possibly a problem with the 3rd preamp valve, V3. That is the one furthest from the input jack socket.

I'd try swapping that out with a known good preamp valve for starters anyway.


Andy.

[Jondog]

ditto

[fiveightandten]

...or one power tube going down. Don't play the amp outside of troubleshooting it until it's sorted. If a new PI tube, as Andy suggested, doesn't do it, swap out the EL34s.

-Nick