digital effects rack humming?!?

[jkhuri44]

hey guys,

ive just bought myself a roland RSP 550 effects processor from the early nineties, it does delays, reverbs, phase, flange etc.

ive also got a roland SRV 330 reverb.

Both are from the same period...

the rsp 550 makes a meaty humming sound when i hook it up both in the studio and using it with a guitar and amp.... (less obvious in the studio)...

does anyone know what this could be? ground loop??? and how can i fix it?

[Howard Jones]

You mean, acoustically - in the air? Or the signal coming out of it is noisy?

[jkhuri44]

nah, the signal coming out of it has a hum...

and i was just playing with it now and i noticed the noise gets heaps louder when the bypass button is pushed...

strange.