Hi Mike,
I also have a nice pair of 846B's. I bought mine new in 1975. Right now I am powering them with an MX110 and an MC240. They are box stock but I have been considering the 902 up grade myself. I would also need to consider a XO upgrade as well since the original N800's are considered minimal.

I admit I'm ignorant with the technical stuff. I'm just looking for suggestions for a good replacement.

Please keep posting your progress.
Thanks...