Problem Rytm mk1 - noise

Hi there,
maybe you can help me:
After around 45 minutes, my analog rytm starts to make really bad noises when i want to play back larger samples. I postet a small video as an example.
When i switch it back on and off, the problem is gone again.
As i sayed, the hum/whistle appears on pads with larger samples, also on all tracks and kits. The frequency of the noise is always tuned to the pitch of the sample, i already checked the delay/reverb/compressor.
Thanks for your help,

Hvisa - 1.m4v (4.2 MB)