Reverb Squeal?? Confused!!!

[lookslikemeband]

Hey gang -

Just found another Reverend Hellhound 40/60 head. Sounds good (as I expected!).

But when I turn up the reverb over 8, it starts to "squeal" and gets a bit noisier (as if I'm turning up the gain, like a bit of an AC "hum").

I swapped out the reverb tube with a new 12AT7 - nope
I swapped out the V1 tube with a new 12AX7 - nope.

Anyone think it's my 6L6's, or something else??

ALL help is appreciated!!!

Thanks.

Lance

 

[Guitarzan]

Perhaps the noise is happening earlier in your preamp chain??? Have you tried taking a "Sharpie" to your preamps tubes? Just turn your amp on and tap the tubes individually with something non-conductive. ie "Sharpie" or similiar. You should be able to pick out the culprit when your tapping is translated through the amp.

 

[lookslikemeband]

REALLY??? That would work?? Wouldn't the tubes get damaged (even when lightly tapping)?

Cool... I'll try it tonite....

Dude... I'm gonna blow my face off!!!! :lol:

 

[Guitarzan]

No it won't damage the tubes...haven't you seen the picture of "Sharon"weilding the hammer on the boogie site? Seriously just a small, light tap to the tubes is all you need to do. You'll know which one is microphonic...It will be obvious. Just use something "non-conductive", you'll be fine.

 

[Bloozman]

I have the same problem with a Mesa LSS