Marshall Class 5 Master?

[plexi50]

I have a friend that would like a master volume put in his Class 5 amp
Im not thinking so straight today but cant i just split the treble pot like any other marshall master volume?
Something doesnt look right about doing it that way though with this circuit. One of those dummy days

[plexi50]

I wired it as a standard mater pot and it works fine. 

[jeff]

what exactally do you mean by split the treble pot?

[plexi50]

I take an axe and split the treble pot in half. Then super glue back together. Something in the super glues fumes makes tone better.
Just kidding. What i ment by spliting the treble was just running the treble pots wiper to a 1MA pot and on to the PI

[HotBluePlates]

I wired it as a standard master pot and it works fine. 

Looking at the schematic, I'd think you'd replace R24/R26 with a 500k pot, or replace R14/R11 with a 1M pot. What did you wind up doing?

[plexi50]

HBP i wired the treble pot wiper to a 1MA pot and out to C21. But not enough gain and is acting more like a secondary volume pot now. I was thinking i needed to look farther down the preamp

[darryl]

I was thinking i needed to look farther down the preamp

An effective position for a master volume would be, as HBP indicated, between V2B and V3A. Replace R26 with a 500k log pot, but leave R24 in place. R24 is probably there to avoid blocking distortion, and it would still be needed when the new master volume control was set to its maximum.

[plexi50]

Good advice guys. Thanks for the tips and info. Im fresh 1 hour out of surgery and im wacked right now. Id like to tell you that they found an old 12AX7 in my knee cap but it wasnt so. Better luck next time i suppose. I will make the changes next week when i can move around better