Microphonic Tubes

[Twitch]

I think that the tubes in my Pro Junior are microphonic. I'm hearing some very strange noises that do not sound like amp hum or 60 cycle hum. It sounds like wind blowing through a microphone. I also get some odd oscilating tones at times. When I hit the tubes right I also get some odd sounds, thus my assumption that they are microphonic.

Is it bad to play with microphonic tubes?

 

[Lewguitar]

Re: Microphonic Tubes

Sounds like what you think: microphonic tubes.

Tap them with your finger and see if the noise changes. If it does, even it gets better, you've got a problem with noisy tubes or a dirty tube socket.

Lew

 

[Twitch]

Re: Microphonic Tubes

When I tapped them earlier the noise changed dramatically, almost as if I had turned the volume up. Now I'm just getting some tube rattle when I hit them.

 

[Lewguitar]

Re: Microphonic Tubes

When I tapped them earlier the noise changed dramatically, almost as if I had turned the volume up. Now I'm just getting some tube rattle when I hit them.

Sounds like it's time to replace a couple of them...you ought to keep a few new and good extra tubes on hand. That way you can pull a suspect tube and replace it with a known good tube and see if the problem disappears with the new tube. It'll save you money in the long run...Lew

 

[Twitch]

Re: Microphonic Tubes

Thanks Lew. Any danger in running these tubes for a couple days until the new ones come?

 

[Lewguitar]

Re: Microphonic Tubes

Thanks Lew. Any danger in running these tubes for a couple days until the new ones come?

Probably not. Good luck! Lew