single Cambridge audio azur 840w vs bridged mono

More detail and focus is a power conditioner...
Doubling up amps is not going to get you more detail and focus.
In fact IMO it will be less.
So I would start looking foor power conditioners, and/or some power cords..

I have an Azur 840W and I always thought it sounded great, then I got a pair of Parasound Halos. But when I had the 840 I used it with a power bar, then I tried it right into the wall, dedicated lines. The improvement was amazing! I now have a PS Audio Power Plant and it makes everything plugged into it better. So, if you have the amp plugged into any sort of limiter you are not hearing what the amp can do. A power device like the other Audiogoner recommends would be a good idea. Don't scrimp on this, it will improve everything! Even my VPIClassic sounds better! If you were bi-amping, I would use each amp for one speaker, but I think the issue is quality, not quantity. Good luck!

I don't any experience with the Cambridge 840W but do have experience bridging a pair of Pathos Classic One MK III integrated amps. I read the reviews of both amps (bridged) at Dagogo by Doug Schroeder. Since you didn't ask about the Pathos amps, I won't bore you with too much detail about them but suffice it to say that bridging seemed to bring everything significantly closer which made it far easier to hear detail clearly which had been previously obscured or merely hinted at. The only downside I heard was a diminished sense of depth. The furthest sounds now seemed more immediate thus the acoustical environment seemed foreshortened. All in all, I would consider that a fair trade.