Hello,

Newly purchased pedal with original power supply gives me this disturbing high frequency sound when engaged. It’s like feedback but continuous and always same level and pitch.
It’s subtle but audible. It goes away when pedal is off and when i set treble knob to zero. I used true bypass mode and now i’m using buffered mode. no difference.

my setup is simple. I have les paul > polytune > soul food > jvm205h
Tried even without polytune but no difference. Amp is set so it cleans up with dynamic picking and by rolling of volume knob on the guitar. e.g not so much gain.
Pedal is set like
Volume: 10 o’clock
treble: 11 o’clock
gain: 9 o’clock

With soul food off it’s dead quite. Cables are of good quality and new.

Is pedal picking up something in the room?
Do i need isolated power supply?

When i tried it in the shop i did not hear this but now i’m kind of unsure. Shop is far away from home so no chance to go back and try it there again.
I guess i could try 9v battery but that’s not a longterm solution.