Toning Down the Lead Channel of a Studio .22+

[RR]

Is it the first preamp tube nearest the input jack that I should replace this 12AX7 with say a 12U7 or something or rather?

I replace this preamp tube with a 5751 tube and the gain is still fairly high. I'm looking for a mild break up. Any thoughts?

 

[LHanson]

Yes. The preamp tube to the right, facing the back of the amp.

Just in case you don't have the manual:

http://www.mesaboogie.com/manuals/Studio%2022%20Plus.pdf

Cheers.