For some reason it sent my Diamond Compressor up the wall in terms of noise just by placing it anywhere on the pedaltrain. Take it off and place in the floor, no noise. Very weird indeed. I noticed a tiny amount of hum from a TC Corona but only when placed directly on top, but you had to t listen for it with headphones to pick it out.
My signal chain is virtually silent right now. From bass, through the board, M900 amp to PJB Bighead, not an ounce of hiss or hum since I ditched the EBS flat patch cables!