Hi guys,

I recently bought a fantastic Korg Mono/Poly which unfortunately has a strange noise problem I didn't noticed when I picked it up.

I hope you guys know this synth better then myself and can give me some help figuring out if there's something to recap. The noise I'm talking about it's different from the typical noise floor every analog unit has. 

I tried to do the following test and I have attached an audio sample:

First part:

- All VCOs vol =0 / Cutoff =0 / Noise = 0   ( I change the attack and release time knobs in the vca section)

Second part:

- 1 VCO vol=50%  / Noise =0  ( I change the cutoff and attack time knobs)

As you can hear the noise is very audible at low cutoff value and it's not affected by cutoff, vco volumes, resonance. 

What do you guys think could it be Could it be a VCA problem  

Thank you in advance for the help.