High Frequency Noise

[60pfennig]

After soldering and assembling everything I tried 8knobs out. Everything works good but I get an very high pitched noise even if all oscillators are turned down. Is this because of the the arduino or did I made a mistake while soldering and there is flowing some current where it shouldnt flow?

[SubstanceD]

Can be due to arduino or it can be one pot as well.. rapidly check which one is the culprit . This can be done by turning all pots down and rapidly turning one single pot to somewhere 30%-40% and bringing it back down to 0. Do this for all the pots.
If its on pot then its the soldering of the pot if not then its arduino. If its arduino then on the backside of the pcb you can solder an additional register anything between 10 to 100 ohm deadbug style.

If its pot then the easy fix is everytime do this action to the pot to cancel the Hi freq noise. ie bring it to some point like 30%-40% then rapidly bring it down.

EDIT: additional register would be on the audio trace not on the midi trace

[60pfennig]

Ok, I cleaned all pcb because I thought maybe maybe the flux caused a current leak. Problem persists. I tried the knob thing. Every knob is modifying the volume of its osc. The hi freq still persists all the time on the same freq. On poti might be faulty, because even if I turn it completly down, the osc keeps playing on low rate.
To solver the hi freq problem I could try soldering an additional resistor. Where exactly should I solder it?

[SubstanceD]

Ok..
R1 would be the place

[60pfennig]

And I would take out the old one and replace it? If I solder it in parallel it would be useless I guess. I'm not that good in electronics, sorry! :)
Also I measured the pins I soldered with a multimeter and I was a little bit confused. All pins of the 6 pin connector seems to be connected and power is flowing between the pins. Did I somethin wrong or is it on purpose. I thought every knob is "sending" its resistance to the arduino via these pins. So I don't understand why these are connected.

[SubstanceD]

True Parallel would do small change. If its precisely high frequency then it has to do with the register and capacitor relation?
Is it possible for you to know what is the high frequency ?

Is this it? 16k ?

[60pfennig]

Hi, sorry for the delay. Yes my noise is also at 16kHz. This is what I get with every knob turned down..