Best Answer phil_m , 23 July 2017 - 07:24 PM
If you put a dummy mono block, such as a Gain block before the output block, the output would be dual mono, so if you wanted to only use USB 1, you'd have everything mono-ized.
You could also easily just combine USB 1/2 in your DAW to one mono signal. In Reaper there's a option to downix stereo tracks to a signal mono track. Go to the full post