Shecter C-1+, noticed it as soon as I could take it to a decent volume. If it's turned all the way clockwise (lefty) I don't really hear it. The other direction however, becomes generally unmanagable.

Any ideas? Actually gets considerably worse when I pull the knob out for the coil-split.
'08 Shecter C1+ w/jb-jazz
'10 LTD Deluxe EC1000 w/Blackouts
Peavey 6505+
Peavey cab
Line 6 Pod X3 Live
ISP Decimator