London Power 3 channels amplifier project

[Vostre Roy]

Hi Vostre
Your figure shows conceptually what the 7211 does, but it looks like a DPDT and needs a jumper on the back to have this functionality - otherwise it defaults to the pick-up selector function.
Also, because the relays have two states, you have to decide on what the default state selects channel-wise, i.e.e, no relays on = clean, but could just as easily be over-drive. It depends also on what aesthetic you want for the switch positions, which are in a fixed order mechanically, but you can assign the result as "increasing gain" or whatever, if that is clear?

I think it is, but lets see if I understand you correctly ahah

Basically, if I connect:

Relay-1: ML-1 to NO and Clean Mute to NC
Relay-2: ML-2 to NO

Then the switch act like the picture below (I think my first one was confusing, hence this one being a bit more clear on what I wanted to show):

   

I've deleted the pictures that were not good as I've reached my attachment quota lol

Cheers!