Conrad Johnson 140 or 12A monoblocks?

The cj prem140 will have a tighter bass where the 12's will be a little looser and sound slightly bigger. The mids and treble wil be quieter and more transparent with the 140 and the 12's will be IMO a little more musical and have a bit of that classic tube wamrth.
I don't beleive the modwright tube amp is very "tuby" sounding so the addition of the 140 may become too neutral depening on your tastes.
personally I would buy the 12's but I like a warmer kinder to recording sound.

Thank you Downunder! This is very helpful. I will try to get the 12's, if I can find a pair.

I would go with the 12 - more musical and in sinergy with the rest of your system.

The 140 is clearly the better amp without question. It is neutral, clean, effortless and musical. It is simply natural. The Modwrigth is neutral with no edge or hint of sterility. I agree with Downunder it is not tuby and that is how it was designed and is why it out performs preamps 2-3 times it price. I cannot imagine being too neutral. You are neutral or colored. If you want pure music, the Modwright with the 140 will get you there. Of course, you may find your wires and speakers needing updating if you go with the 140. If you want musicality and specificity, then the best CJ - Modwright combo is the Premier 350 and if the 350 is more than you want, check out the Channel Island D 200s.