I have a Yamaha solid state DG130H head running into a 2x12 Avatar cab. (effin amazing amp btw!) However, I'm having a problem with the effects loop, especially with non-stomp box f/x. When a Yamaha DG Stomp multi-effects unit (used only for phaser, Flanger, etc) is used in the effects loop, it sucks a part of my overall sound, NO MATTER if the particular effect on the Stomp is on or off. Hard to explain, I know, but the overall tone, just with the stomp plugged in, is a bit more "hollow", as if some faint phaser effect was on and stuck on some frequency... or it kind of sounds like a faint wah pedal left in one position, somewhere near the middle of it's range. When I turn off the power to the DG stomp, the amp's normal sound returns and I'm good to go (sans effects). I duplicated the setup using a Digitech Rp5 (oldie but goodie), again, just for the effects, and got the same results. As before, the "sound sucking" was apparent no matter if I had the effects unit bypassed or the actual effect turned off. As long as the effect unit had power, the sound was adversely affected. I've tried adjusting the "MIX" knob on the back, and it didn't help improve the sound issue. Of course, turning the knob all the way to "dry" did get rid of the problem, but again, no effects. When I ran a single flanger stomp box, the tone did not appear to suffer. Any suggestions?