Thanks Kjung!
So, if my understanding is correct, plugging into the effects return would "mute" the signal coming from instrument input and only the signal from effects return would be treated further and sent to the speakers? I would then have to unplug "effects return" whenever I need to use to the instrument's input?
If that is the case, you've got my question answered spot-on! And a very useful argument in favor of the Bonafide. I confirm there's one effects loop per channel on Bonafide.
Depends on what type of effects loop it has (parallel or serial). With the Markbass Little Mark you can run instruments in the return and front simultaneously. You'd only have gain adjustability on the front input.
Edit: according to a review it's serial so using the return would break the path from the internal preamp.