Hello, having trouble routing output signal to an effect. I have a ufx plus and an older ufx adat connected and locked. I am using analog channels 1-8 on ufx plus to mic my drums and then using channels 5-6 on older ufx to route stereo in and out to and from my unit. When i listen to the sound(even when bypassed) i hear a high pitched ringing noise almost like a ring mod, in particular on my toms and gets printed when i record. This sound however, is not there on the analog channels 1-8, only on the routed signal. Tried dif cables,dif mics but still there…any ideas?