Thank you for your answer Florian. You are right about the two noises, I didn't noticed the 50hz buzz.
I recorded a new file with VCOs vol at 100%. EG intensity is at 0.
At high cutoff settings the noise it's not so easy to distinguish but, at low and medium cutoff settings, it's imo very audible, especially listening to the recording with headphones.
Maybe it's a normal thing of all Mono/Polys, I don't know. The thing that made me think there's a problem with mine is that it's not a noise floor , which is always present even if no key is pressed, but it's something that pass thru the VCA and goes to the output, even with all VCOs at 0% volume.