Scratchy sound

[Clubman35]

Hello,

I just tried posting this same question a few minutes ago, and even though it appeared to be submitted, it's not showing up in the threads. If it pops up twice, I apologize.

Okay, having a problem with my Peavey Classic 50 Head. I'm getting a strange, scratchy, distorted sound when I play low notes or chords. Sounds the way a scratchy potentiometer would sound. Happens on both the clean and dirty channels. I have replaced all the tubes and the problem persist. Any ideas?

Thanks-
Jim

[chris661]

Sounds like the speaker may be knackered. Can you test the amplifier with a different cabinet?

[Michael Bean]

Loose tube socket contacts?

Mike

[Printer2]

Could be a dirty pot and the low notes vibrate the wiper. If it does it when the amp is played quietly then it sounds like maybe a coupling cap leaking DC?

[indianajo]

Tube amps are rather dangerous. You need to read the hv thread for newbies at the head of the tube forum, or aikenamps.com technical resources button, technician safety button. You probably have a loose connection, either a potentiometer, or something else. Poking around at things with a plastic stick or a dry wooden dowel, to see if the scratch is located a particular place, would probably be safe. If it is a potentiometer, try spraying it out before replacing it. Aliphatic hydrocarbon contact cleaner from the lumberyard is highly flammable, no smoking, open flame or pilot lights, electricity turned on or off within 30' of the spray. Non-flammable contact cleaner from the electrical supply house (contains brominated or florinated hydrocarbons) dissolves PVC plastic contained in consumer devices.

[Clubman35]

Thanks for all the advice. I'll see what I can come up with and post back.