I'm trying to bounce down a stem mix from my desk using the UFX to record 16 channels of audio at the same time to my DAW (I'm using a Clarrett Octopre off ADAT to achieve the extra 8 channels).

The stem mix has been coming back with different levels than those set in my mix, so not a true representation of my mix.

I've created a new project with the same audio on each channel to try and work out what is going on.
The main issue seems to be between channels 1 and 2 which seem to receive the signal 5db lower than those on 3-8 (the set of channels assigned to the octopre have their own issues, but I think that might be a question for another thread).

I'm guessing this has something to do with the fact the first couple outputs on the back of the UFX are XLR instead of jack. I've set all of the outputs in Totalmix FX to +4db (which seems closest to the signal going out of my DAW), but still there is a disparity in settings for the first 2 channels to the rest. I'm connecting my UFX to the desk using a loom with jacks at the UFX end and D-Sub going into my desk. I've had to put XLR - Jack adapters on the first couple channels to connect it to the UFX, could that have effected the signal level? (I wouldn't imagine it would, but thought best to mention anyway).

Is there a way round this, so I can get the same levels across all channels?

Any help greatly apreciated.