I too am having excessive hiss issues with the mixing link. Using a DPA mic to XLR mic input with phantom, DI/Line out to the desk with LINE selected on the bottom of the box there is this incessant excessive hiss/noise. I have tried every imaginable permutation of gain adjustment/different lead/pad settings on the desk etc and still the same. Even worse, when the FX loop switch is toggled to on it doubles the hiss/noise whether or not anything is connected to it! Can anyone please help me? I have been tolerating this for months but really need to make this a useable device which at the moment it just isn’t. I really hope I am doing something wrong, please advise.

FYI:

Settings: Input Gain LOW (and dial on zero)

DI/LINE: LINE

GND/Lift: GND

One interesting (but worrying) note: if I set the mix selector switch to MIX and engage the FX LOOP button to ON and I touch the metal mix selector switch there is a really loud hum, the kind you get with a bad earth. Could this simply be a faulty box?!

Thanks