I have a McIntosh C2500 and a pair of JL Audio F113V2 subs and the "A" output on the preamp connects it to an MC452 power amp and the "B" output connects to the JL Audio subs.
In my case I use the XLR outputs in both cases, you could do the same using the single-ended (RCA) outputs.
In my case I use the XLR outputs in both cases, you could do the same using the single-ended (RCA) outputs.