Volume drop on clean channel when warm. Help.

[happythrasher]

(Rev G Dual Rec)

Hi there,
After about thirty minutes of playing loudly I seem to get a big volume drop on the clean channel.
If I switch it over to Variable High Gain on the back, it goes back to normal. The other channel is totally fine.
I'm guessing this is a preamp valve issue?

Thanks in advance

Will

 

[domct203]

(Rev G Dual Rec)

Hi there,
After about thirty minutes of playing loudly I seem to get a big volume drop on the clean channel.
If I switch it over to Variable High Gain on the back, it goes back to normal. The other channel is totally fine.
I'm guessing this is a preamp valve issue?

Thanks in advance

Will

Welcome to The Board.

Be careful what tubes you use in V3 & V4. These are cathode follower positions and have been known to make sub-spec tubes fail. Tubes that have proved reliable for this are any Chinese (Shuguang/Penta), JJ or early NOS. Do not use New Sensor tubes as they have proven unreliable in cathode follower use. New Sensor brands include Sovtek, Electro-Harmonix, Tung-Sol reissue & Mullard reissue.

Read more here: http://www.forum.grailtone.com/viewtopic.php?f=4&t=25102&start=19

I hope this helps,
Dom

 

[happythrasher]

Thanks Dom.
I'm going to replace the preamp tubes I think. (after a little more research on here)
I that the likely suspect for the volume drop on one channel then?

Cheers,
Will