AC30 Squealing

[dave34346]

So , I set the gear up last night , same as always ,
Switched the amp on , and it started squealing like a pig ,
Removed all the fx , tried again with the guitar straight into the ac30 , and still did the same .

Im guessing its a valve problem. Going to investigate this morning .

Any idea's .

Regards
Dave

[Goingdownslow]

Hi..if the amp is feeding back on its own with nothing plugged in then it is probably a microphonic preamp valve....ecc83...

If you get the chassis out of the cabinet and power it up connected to the speakers of course you should be able to identify the valve by gently tapping each one with a pencil....if there is a faulty valve it will be apparent quite clearly....

Cheers, Paul