I have come across an annoying problem here. Whenever I use the HX Stomp in the FX Loop of the H&K Grandmeister Deluxe 40, the amp becomes noisier and more prone to feedback on the high gain channels even with conservative gain settings and no boost. This constantly happens, no matter if I I do the 4CM or use the HX Stomp In/Out only in the GM40 FX Loop.
I started checking the amp FX Loop with a straight patch cable, different pedals etc. and only when the Stomp is involved, the noise issue arises. So it´s not the amps loop that´s failing
I´ve tried switching between Instr/Line levels, different impedances on the HX Stomp input, increasing/decreasing level gain on the In/Out of the Stomp but so far to no avail.
Help anyone? Has someone maybe encountered the same problem with other amps?