Yup, the 10 Megohm input impedance and the gain of the EF86 are a little ruthless in exposing noisy pups, pots and switches in a guitar, particularly if the amp is run with no negative feedback on the clean/crunchy control. Good grounding in the AC mains wiring is important too. At work my Tode is very quiet with a guitar plugged in. At home where my safety ground is pretty old I get hum from my guitars when plugged in. Time for a new ground rod this spring.