Hello!
I have recently bought preenFM 2 and there's one thing that bothers me a lot - my unit produces a constant, very thin but loud noise at 13,5kHz.
Here's how it looks on a spectral analyzer:
This is of course very easy to filter out completely due to nature of the noise, but only on digital EQ's using a computer. Not so easy in hardware-based setup though and the sound is very harsh and unpleasant to ears, especially on headphones.
The noise seems to be independent of filters (I tried to put 4 separate filters on every instrument), volume knob (volume does not affect produced noise in any way) and also of power supply (appears on both USB power and DC - might be a tiny bit louder on USB but it's not a big difference 2-3dB tops - you might notice it if you look closely at the spectogram on the left side of my screenshot - this small peak is when I plugged USB cable in. Low noise appears across the whole spectrum after USB cable is plugged in, although much much lower than this 13,5kHz peak).
It also does not change at all no matter what preset is playing and how many parts are in use.
Overall I'm very happy with the instrument and I think Xavier did a WONDERFUL job in designing preen's interface, this is the very first hardware FM synth that I find accessible and actually fun to use. I would love to keep this device but currently this noise bugs me a lot.
Do you have any ideas what could be the reason here and can you tell me how I could possibly fix this issue?
Thank you!
