Scratchy pot at power up??

[riscado]

is there any particular reason why an amp should have a scratchy volume pot right after power up, like as soon as standby is off (amp fully operational) the volume pot is scratchy for about 1/10th of it's taper and only happens for a few seconds.

Also it's very noticeable if humbucker guitars are being used. after this small period the scratchyness disappears.

any ideas, can't read any DC across the pot.

[Funkalicousgroove]

try cleaning it and get back to us, if that doesn't fix it could be something else.

[riscado]

tks

[riscado]

I haven't removed the pot for cleaning yet,but it occured to me it can't be dirt, since it only does this right after power up, than the noise is gone.

[UR12]

Sounds to me like you may have a leaky cap leaking dc onto the pot untill the amp voltages stabilizes. Maybe try changing the coupling cap going to the pot. Just a thought

[Richie]

And also try using a different preamp tube.or a funky ground connection. But it does sound like a leaky coupling cap.

[paddy]

Sounds to me like you may have a leaky cap leaking dc onto the pot untill the amp voltages stabilizes. Maybe try changing the coupling cap going to the pot. Just a thought

+1 Had the exact same fault with a Marshall last month,try the
coupling caps

cheers
paddy