So I think that I want to try a Ring Modulator

[Derringer]

and I have all of the goods to do that (maybe not the transformers but it's not like they're rare), I just don't want to bring my signal generator to gigs

I got the CA one sounding pretty gnarly with minimal changes. It made less noise through my PA than it did through my Little Gem. I'm attributing that to using a true XLR cable going from the RM's output (used a hi-z/low-z converter) to the mixer input.

[Derringer]

finally got this all wrapped up and used it last night at a gig ... sounds cool
and now that it's all boxed up, the tone switch definitely makes distinguishable differences.

took a novel approach to shielding and securing the guts (I always think of standoff tabs too late in the process





I used the GGG layout and found an error ... pins 4 and 5 need to be connected as well as pins 6 and 7 of the 565 chip
I didn't find it till after everything was soldered in so just flowing two little solder bridges did the trick.
Otherwise I made the input cap 1 uf and lowered the input resistoor to something between 22K and 47K (honestly forget now)
I changed the output cap of that first opamp stage to 1uF too.
I also fabbed in a 1M pulldown resistor directly onto the board going from the input to the nearest ground connection.
I believe everything else is pretty much stock. I tried it with the 33K resistor on pin2 of the 565 jumpered and it just made the ring sounds louder, so I left the 33K in.
And the power supply is just a charge pump set up for bipolar operation.