Are there any known noise issues with the Direct out on GK MB500's? I'm getting substantial hiss and some crackling on the DI out even with nothing plugged into the amp with the EQ bypassed. Switching in the EQ increases the amount of hiss and noise proportionately, and the ground lift has no effect either way. The hiss and crackling don't seem to be there at the speaker out into the cabinet. (Eden 210 Nemesis) Comparing the GK DI to the signal coming off a JDI direct box into another channel, The JDI is dead silent with both channels matched to unity gain, while the GK is full of hiss and crackling. (It's the crackling that makes me think there is something about to give in the amp) I've already swapped mic cables and mixer channels and the noise is always there. Thanks for any insight.