I used with guitar pedals and all have loud 60 Hz hum and high pitched crackling noise.

Works great, no noise.

Works great, no noise.

cleared up the hum noise on my delay pedal!

Powers all my pedals but either buy the planet wave one for the same price or you'll need to build an external noise isolating circuit.

Works OK for digital, noise stays out of signal

cleared up the hum noise on my delay pedal!

I was hoping that I'd have a fairly noise-free pedal when using this, but as soon as you plug this in, you get an obnoxious high-pitched buzzing sound coming through your amp

Had to put a different power supply on this, as theirs put aweful noise into the system.