Moog Music Forum

Hello, my Model 15 reissue's 921B and 921 both output a high-pitched squeaking noise if I adjust the range knob too slowly (as it's between two octaves) while audio is playing. If I adjust very quickly, the squeak is less noticeable, but this small burst of noise is visible through an oscilloscope. Just wondering if this is normal... & is this also the expected output if the range pointer is intentionally held in between two positions?

The only other Moog I have nearby is the Subsequent 37, which doesn't have this behavior.

Thanks in advance

I'd say it's normal. I'm not near my 15 at the moment but I know that the range knobs on vintage Minimoog's can exhibit that symptom.

Those rotary switches have different characteristics... break before make, make before break etc... the electronics are experiencing these characteristics and responding to them.

Usually you wouldn't change the footages whilst actually playing so it's not a problem.

Cheerz
Tom

This is a normal thing. It does happen on most multi-position octave switches on synths. These switches use contacs. And there is a short moment when neither or both contacts are connected. Most of the times it is no connection in between.
Welcome to the real analog domain of physical switches and pots.

Interesting, I suspected that was the case and just wanted to confirm. Thanks to both of you!