Hey folks, I've had this

http://www.korg.com/gear/info.asp?a_...&category_id=6

for a few months now, quite happy with it, however, in any mode of operation other than by-pass for tuner there is slight noise/hum if no playing is going on, almost like it is processing the low quiet signal input ?? The only thing I can think of is some kind of AC noise when running off the AC adaptor, but then it should make noise even in by-pass..

Any ideas ?

thanks

Ted.