I have my setup in the traditional 4cm ...HX Fx send to tubemeister guitar in.....HX FX return to amps FX send....HX FX send to amps FX return and guitar into the mono input. The loop in my amp is on , the amp is on the clean channel and the HX effect chain the blocks are in the following order: compressor, distortion, FX loop, chorus, delay and noise gate. If the HX effect loop is off the distortion (from the HX effect) sounds fine. As soon as the loop is active the sound gets thin and harsh. The effect loop on my amp remains on at all times, and as expected if i shut the HX effect loop block off, i can only get the power section of the amp, not the preamp distortion