Loud buzz from speakers

[Liv3rman]

I turned on Ashdown MAG 300 amp, and out of the blue came a loud, almost deafening high tone which I can only describe as resembling a seriously amplified electric razor. Anything I do to any of the controls has no influence on the tone, and it plugging in or unplugging bass has no effect. Haven't been moving the amp, haven't spilled any beer on it. It has just been sitting peacefully in the corner of the livingroom, used daily as a home-practice amp. Was wondering if anyone has had a similar experience, or what could be the cause?
I am guessing it has DC voltage at the output socket, indicating a blown transistor or capacitor?

[RickenBoogie]

It needs to go to a qualified amp tech, where it can be tested with the needed equipment you or I don't own. It's your only option. Best of luck.

[MontanaBassDude]

Something like this happened to me once - a loud, continual raucous 60-cycle hum through my speakers... but through no one else's. In my case, I finally discovered it was one of those adjustable wall light switches up stairs, half on, lights dimmed. I have to always make sure it's either totally on or off when the band is rehearsing downstairs. Strange but true. AC fields create some strange things. Check any of those rheostats in your house.

[Liv3rman]

Sorted now thanks guys. A new smoothing capacitor and a bit of solder repairing. Found a guy locally who did the lot in an hour for only £30. Well chuffed.

Anyone in the midlands UK with amp trouble check out
www.proaudioservices.co.uk.