Moog Music Forum

I'm finding that with my CP-251, whenever I try to send from the mixer output or one of the attenuator outputs to my guitar amp, I get a quiet but very noticeable high-pitched whine. This sound is the same no matter what's plugged into the unit (including when nothing at all is plugged in except for the line to the amp), and it is the same with a variety of power sources on a variety of circuits. It's also the same out of all the jacks I've tried sending audio from (Mixer +, Mixer -, and both attenuators).

Is this a normal thing? I didn't buy the unit expecting to output audio, and it seems to work perfectly for the CV stuff, so I don't know if the whine should be considered a flaw or just the way things are. And if it's a flaw, does anyone have any information about what might fix it? Thanks...

you might be picking up radio waves, interference?

Hi narrowcaster.
How are you powering the CP? Is it sharing a power source with another device?

The CP does whine when it is powered by some non-Moog power supplies or if sharing power using a multi-pedal power supply. Don't know why that should be.

Suburban ... Might be, but it seems a little too consistent for that (doesn't have the variability I associate with RF interference).

dr_floyd ... So far I've tried it with my Voodoo Labs power supply, but also with the original Moog adapter plugged into its own jack on my Furman Power Factor. There were other things plugged into the Furman at the same time though. I'll try putting it on a completely separate circuit, with the original adapter, and see what that does.

narrowcaster wrote:I'm finding that with my CP-251, whenever I try to send from the mixer output or one of the attenuator outputs to my guitar amp, I get a quiet but very noticeable high-pitched whine. This sound is the same no matter what's plugged into the unit (including when nothing at all is plugged in except for the line to the amp), and it is the same with a variety of power sources on a variety of circuits. It's also the same out of all the jacks I've tried sending audio from (Mixer +, Mixer -, and both attenuators).

Is this a normal thing? I didn't buy the unit expecting to output audio, and it seems to work perfectly for the CV stuff, so I don't know if the whine should be considered a flaw or just the way things are. And if it's a flaw, does anyone have any information about what might fix it? Thanks...

i've encountered this exact same problem when sharing power w/ my VX unit for the voyager, but outside of that I don't know what would be causing the problem. Are there any specific connections that are generating the noise when you patch w/ it, or is it any connection point that you hear it from?