I get no audio from anything I plug into the Audio Input jack

[Aimbit]

I tried plugging in a microbrute and a guitar into the Audio Input jack and I get absolutely nothing coming through.  I turned up all my envelopes, I tried gate/no gate, inst/line, the gain knob.  I have the external mixer knob turned up and going into the filters.  I don't know what I am missing.

[DrJustice]

Starting from an Init patch, cranking up External in the mixer and assigning it to the filters should be all that's needed, so I don't think you're missing anything. You need to press a key to hear anything of course, unless you've set the external input Audio Gate to On - it sounds like you have these things under control though.

The Gain knob can potentially be perceived as the "wrong way around" when you reach around the panel to turn it up. Other than that there should be no "gotchas".

[daveowilliams]

This may sound obvious, but the sockets are very stiff on my MxB. Make sure the jack is fully pushed in and seated. This caught me out at first.