ROG May Queen/Ruby combo

[caprotesta]

I decided to try to create an distortion effect/amp combo. Because of their simplicity, I chose Runoffgroove's May Queen distortion and Ruby amplifier. Both circuits are breadboarded on the same board. Individually, they both work fine. But when feeding the output of the May distortion into the input of the Ruby amp, I get a very high-pitched squeal coming out of the speaker. Any ideas of what could be causing this? Or how to fix the problem? Should I put a low-pass filter somewhere in the circuit? If so, where, and of what values?

May Queen schematic: http://www.runoffgroove.com/mayqueen.html

Ruby amp schematic: http://www.runoffgroove.com/ruby.html

Thanks for any/all advice.

[LucifersTrip]

do you have 2 vol pots...one for each? ...or did you eliminate the MC vol control and just feed full vol into the Ruby?

I would leave the vol pot in there for the MC, lower it a bit to see if the squeal goes away, then sub with fixed resistor(s).

[Perrow]

And when he says MC, he really means MQ or May Queen

[caprotesta]

I still have both volume pots installed. I'll give that a try and see if that fixes the problem.

Thanks!

[Davelectro]

You need to decouple the power supply, just like in full-sized amps.

[tca]

Decouple from the supply, check  the Marshal mini amp MS-2. Had the same question when building my PUNCH amp with Tube Overdrive Sound as a pre.

[caprotesta]

It looks like decoupling is going to do the trick. I'm going to have to tinker to get the values right, but so far so good. Thanks for all the help, y'all!