I refer you to http://ampwares.com/schematics/concert_6g12a.pdf. A friend of mine retired from playing and gave me his brownface Fender Concert amp.It wasn't working so I ended up rebuilding the circuit board. I managed to not screw anything up; however, the normal channel was way louder than the vibrato channel. I routed the normal channel to the vibrato circuit and vice versa and used the amp for a couple of years. Then I started getting weak or no sound intermittently. So I put it aside and used something else. Then I read on Rob Robinette's site that old tube sockets could give you that problem, so I replaced them all and that seems to be working. But I always wanted to find out why the vibrato channel was lower and address that before I put the chassis back in. I think I finally found it. V1 pin 6 goes straight to a .05 capacitor while V2 pin 6 goes to a 100k resistor, and then a .05 cap. My initial plan was to switch the 100k resistor with the 10k next to it, but I may be messing with some function I don't know about, so I figured I better check with the experts.If that works what about putting a resistor between V1 pin 6 and the .05(actually .047)cap? The normal channel is very loud and starting to break up at 10 o'clock and I would like to tame that a little. Thanks for your consideration on this.