[sammyr]

Hi folks. Was looking at the orange field guide and stumbled on this schematic for an electric amp innovations matamp green type of amp. There's some weirdness to the schematic that I don't quite understand mostly around the fuzz/volume control.

The control is a 1 meg pot, with a brite cap the part I don't understand is why there's a 10k resistor to ground on one of the outer legs of the control and then a 1 meg resistor to ground coming off the wiper. I've been staring at this schematic too long so a fresh set of eyes would help.

As well, I'm a little flummoxed by the "boost control" to my tired eyes it looks like a mid control. Maybe I'm missing something.

 

[jb welder]

Not sure why there is both the pot and the 1M on the grid there. With the 10K in series with the pot, you can't turn it 'off' like a volume, maybe that's what he wanted and why it's called 'fuzz'.
Agree about the 'boost' control, Fender calls that pot in the tone stack 'mid'.

 

[sammyr]

Thanks JB, I had a feeling it was a mid control but sometimes you stare at things so long they all start looking the same. I ended up building out a version of the pre-amp using a marshall superbass style power section with a ppimv. I had a feeling the fuzz control was iffy but I just implemented it as is for the first go around and exactly what you predicted happened. I joked with my girlfriend how its kinda like how in spinal tap the amps go up to 11....well mine starts on 6! I clipped out the 10k series resistor and left the 1 meg on the grid (was too lazy to remove it and I figured it was just going to dump before it hit the next stage).