My tube amp is making a crackling/sizzling sound??

[Guitfiddler]

I turned on my 30R Samamp today for the first time since a friday gig, and it's making a quiet but noticable crackle/sizzling sound. Like someone cooking bacon in the next room.

It only does it with a cable plugged in, tried three different good cables, one is a brand new Monster cable, guitar plugged in or not doesn't change anything, if there is a cable in the input there is the crackle.

Any thoughts?

 

[muchxs]

Hairball?

Seriously, that's what we call it when we have a preamp tube on the way out.

The standard tube amp quick fix... swap the preamp tubes with known good ones. Sometimes you can get away with just re-shuffling them in a pinch, swap V1 into a less critical position.

If that doesn't do it the next suspect parts are the V1a/V1b plate resistors. Time for a tech...

On rare occaisons I find a coupling cap leaking a minute amount of DC. They're best checked out of circuit and if I'm going to take it out I might as well just replace it. It's an "Ah-hah!" moment when I find a bad one.

 

[twangcaster1]

Does it do it with every guitar you plug into it?

 

[Guitfiddler]

Thanks. I'll try swapping them out when I get home.

 

[Guitfiddler]

Does it do it with every guitar you plug into it?

It does it even without a guitar plugged in, just as long as the cable is plugged in.