High resonance-like noise although res is set to 0

The Moog Forum Little Phatty & Slim Phatty Forum
1

Hey,

haven’t been using my SP for a while, so I decided to get back at it today. While playing I’ve noticed some high frequencies in the patterns that just didn’t feel right. So I looked at the spectrum of the SPs output using the calibration preset (fully open filter, no res) and just playing a C3. Seems with the filter set to 3 or 4 poles that noise is there (at 10kHz with 4 poles and at ~13kHz with 3 poles) while the peak is not there with 2 or 1 poles on the filter. I’ve attached screenshots for visualization. That’s not right, isn’t it? What are potential reasons for such a behavior?


Thanks.

Filter Poles: 4
Calibration_c3_4_poles.jpg
Filter Poles: 3
Calibration_c3_3_poles.jpg
Filter Poles: 2
Calibration_c3_4_poles.jpg
Calibration_c3_2_poles.jpg

2

Not an expert, but have you tried plugging the power into different outlets (not in the same room)?
Ive had similar noise on various equipment.. On rare occasions changing the power source helped.