Nano and external pedals with high pitched digital background noise

Nano Cortex
1

I am trying to use the Nano Cortex with external pedals but I can’t get rid of a high pitched hum when doing so. My signal chain is NC > Boss-200 Chorus > Delay > Reverb > Freyette PS-2 > Marshall 4x12. I tried using multiple different power supplies that provide 9v and 12v at 600ma and that didn’t work. Hum eliminator between NC and pedals, no joy. Hum eliminator between pedals and power amp, no joy.

The NC sounds fine when running straight into the power amp, it’s dead quiet. I have tried just one pedal at a time, no joy. Digital pedals vs analog pedals, no joy. A Mesa Boogie High Wire buffer between the NC and pedals, no joy. Everything in the loop of the High Wire, no joy.

I am starting to think I just won’t be able to use the NC with external pedals which sucks because my Midi switching set up depends on it.

2

It sounds like you might have a possible ground-loop hum. How is everything powered?

3

I use CIOKS DC-7 which didn’t help and an MXR Power Brick which didn’t help. As I said, I used a Hum Eliminator which has isolated transformer in all the relevant spots in the in the signal chain and that didn’t help either. Do I need to use a TRS cable from Output 1L into my PS-2? Even though the PS-2 doesn’t have TRS inputs?