Can you hook up a sub to a Consonance A120?

Sure! I did when I had one. It has a pair of line-level outputs. Nice amp. What speakers and sub do you have?

I have this set up in my small office as a second system. The speakers are in-wall Def Tech's so my bass response is limited at best. I was thinking of a small sized Velodyne to help punch up the bass but I am extremely limited with placement. I don't want to spend a fortune because honestly, I never turn the volume up that high anyway, since I'm usually working. But at the same time, I can definitely use some bass help.

That was a great integrated for me if I didn't push the volume too much. I recall that it seemed to have less power than rated. Never measured it, but it just seemed that way. But it sounds like for your application it fits very well. It sounded great. Good, solid, tight bass too. I connected an ACI Titan sub to it and it integrated very well with my mains. Good luck!