Tube Problem?

[Musical123]

Hi,

I recently picked up a used LSC v1 a couple of weeks ago. It is a great amp.

Recently I noticed that sometimes there is a scratchy noise that comes out of it (almost like someone is lightly blowing into a microphone). I tried switching from tube to diode rectifiers but it didn't help and also switched loop in and out with no luck. It also doesn't matter if it is in tweed or not.

I also tapped on on the rectifier tubes and power tubes and all of them made the noise worse (I think that the 6L6 farthest away from the rectifier had the least impact.

The question is are all of my tubes bad? Granted I have know idea how old they are. Any thoughts or tips?


Thanks

 

[jamme61]

It sounds like a bad preamp tube, try checking them, one by one. Do you have a good spare? find which preamp tubes do what (should be in the manual) then you can narrow it down quicker. good luck

 

[dodger916]

That sound is typically a bad preamp tube. Did you test them at all?

 

[Musical123]

I only tapped on the power tubes. I assume I can use any old 12ax7? Meaning there isn't any matching and can mix vendors?


Thanks for your help.

 

[dodger916]

I only tapped on the power tubes. I assume I can use any old 12ax7? Meaning there isn't any matching and can mix vendors?


Thanks for your help.

Correct. It's not like power tubes. Like Jammed61 says, use a tube you know to be quiet and start swapping it with the tubes currently installed.

 

[Musical123]

Thanks, let me try this when I get home.

 

[Musical123]

V2 replaced and it works.

Thanks again.