Are the UR-RT4 transformers responsive when preamp gain is at 0?

Hey folks,

I have a UR-RT4 and also a slew of outboard gear I typically use with the line inputs. However, I’ve acquired a mixer I’d like to use with the front of the RT and still retain the benefits of the transformers. Does anybody know if the transformers will color even when the knobs are at 0?

Thanks!