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AC30 screaming at me

9/19/2005 7:53 PM
David	AC30 screaming at me Hey all, I've got an AC30 RI from 1999 (Made in England, thank god!), that's causing all sorts of pain. She was like this when I got her, so I don't know what exactly caused the sickness, but here's a description of the symptoms: When I first powered up, there was very little sound, and what came out was all distorted and farty, and there was a sqeal that came and went. I replaced the power tubes, and the lo-fi distorted sound went away, but the squeal was still there. I've also replaced the rectifier, but the squeal still plagues me. The nature of the squealing noise is not changed by turning knobs at all. It squeals regardless of whether or not anything is plugged in. I tried pulling the power tubes (first the outside pair, then the inside pair). The squeal goes away when I pull the el84 closest to the rectifier. Another strange symptom of this disease - when the amp is upside down with the circuit board pulled partway out, the squeal goes away. When I reinstall the board and flip the amp right side up (tubes & trannies up), there is a slight click or popping sound and then the squeal starts again. Any suggestions would be very much appreciated. Thanks, David

9/19/2005 7:53 PM

David

AC30 screaming at me

Hey all,

I've got an AC30 RI from 1999 (Made in England, thank god!), that's causing all sorts of pain. She was like this when I got her, so I don't know what exactly caused the sickness, but here's a description of the symptoms:

When I first powered up, there was very little sound, and what came out was all distorted and farty, and there was a sqeal that came and went. I replaced the power tubes, and the lo-fi distorted sound went away, but the squeal was still there. I've also replaced the rectifier, but the squeal still plagues me.

The nature of the squealing noise is not changed by turning knobs at all. It squeals regardless of whether or not anything is plugged in.

I tried pulling the power tubes (first the outside pair, then the inside pair). The squeal goes away when I pull the el84 closest to the rectifier.

Another strange symptom of this disease - when the amp is upside down with the circuit board pulled partway out, the squeal goes away. When I reinstall the board and flip the amp right side up (tubes & trannies up), there is a slight click or popping sound and then the squeal starts again.

Any suggestions would be very much appreciated.

Thanks,
David

Replies:

Don Symes Any signs of scorches or arcing on ... -- 9/19/2005 9:16 PM
Enzo OK, if you pull one particular EL84... -- 9/20/2005 1:59 AM
R.G. So what ever happened? -- 10/26/2005 6:25 PM