Please help me diagnose this amp noise...

[evanjackson]

Sometimes, my amp will make this soft crackling sound...the best way I could describe it is it sounds kind of like the noise you here when someone is, say, handling a microphone and you hear the incidental noise that gets transferred...it's very soft, and seems independent of volume. Any ideas? Thanks!

 

[axolotls]

my amp does this too, and i cant seem to locate the origination. so i would like to know too. it seems to die down after the amp warms up.

 

[donnyjaguar]

I repaired an old Danelectro with the same noise you describe. This was an easy problem to fix - one of the tube sockets was dirty. Try wiggling the tube within the socket (in standby) and see if it affects the sound.

The other culprit for this sound is a resistor (usually plate) that has gone bad. In my experience these resistors can be way out of tolerance and the voltage ampliifer will still be working. A voltmeter is your friend for testing here.

 

[SteveVHT]

More than likely a bad Phase Inverter tube.
Steve

 

[1-Take-Wonder]

More than likely a bad Phase Inverter tube.
Steve

what have you done already?

+1 on tubes, standard tube amp troubleshooting (especially with random noises) is check/replace the tubes, usually starting with power, and then pre-

curious SteveVHT, why did you go to the phase inverter? Always looking to learn more about diagnosing problems quicker!!

 

[bob-i]

You don't mention what type of amp this is.

I'd suspect PI tube or power tube, or connection to these tubes, since it's independant of volume.

 

[Richard Guy]

Don't rule out the computer that is in the house. Try turning it off and see what happens.

 

[evanjackson]

Thank all of you for your help...the amp's a reverend hellhound and it could very well be the tubes (haven't retubed in a while) so I'll check that out. It seems like it's usually the tubes that are the problem
Thanks again!