I purchased as a trial as I like to use EQ pedals in front of my fuzz and or distortion pedals when using a pedal switcher. This EQ induces a considerable amount of noise to your instrument's signal when used in conjuration with distortion and fuzz pedals which was audible when my amp(s) was set to any volume setting above a whisper. I powered the EQ700 with a Behringer power supply, a Donner DP-2, a 1 SPOT PRO CS12, a VooDoo Lab Pedal Power X4 and a VooDoo Lab Pedal Power 2 Plus; the pedal produced significant hiss when engaged even when using ground lifted cables. I used this EQ with nearly every BOSS distortion/fuzz pedal ever made, every Behringer distortion/fuzz pedal that is available from Thomann, ProCo RAT, ProCo RAT 2, Mr. Black's Doomstick, Mr. Black's Doomstick 2 and a Fuzzlord Destroyer v2... Noise and hiss regardless of the gain setting of the pedals. Amps used were vintage Marshall plexi Super Lead (with 12AU7's in V1 and V2), 1972 Marshall Superlead, Fender (silver face) Super Reverb and the pedal was noisy when used with distortion pedals. However, the signal was clean when not using distortion pedals. Guitar was a BC Rich Mockingbird Extreme with Fishman active pickups, I'll try with passive pickups in the near future.