Can I rig a home theater amp to run in wall speakers?


My friend has an older rotel 5 channel power amp that he used to use with a rotel home theater preamp for a home theater.  Now he has a modern marantz home theater receiver that handles the home theater.  His new house has 8 in wall speakers distributed throughout the house.  He has a sonance speaker distribution box.  I advised him to use the rotel power amp to drive the speakers in the sonance box, using the pre-outs from the Marantz.  The current set up can only make use of 2 channels, due to the 2 pre-outs from the marantz, and thus, 3 of the channels in the Rotel power amp are going unused.  I'd prefer to put one pair of in walls at least on its own channels in the rotel, and minimize the quantity of speakers in the sonance box.

any thoughts?
marktomaras
If the Sonance "speaker box" you refer to is their 260 x 3 amp, don't sell it short.  It will do fine with in-walls.

Regarding the 3 unused channels, you may have to use some 1-into-2 rca splitter cables on the Marantz pre-outs.

I currently have the pre-out on my Marantz going to the Sonance to power 3 pairs of in-walls.  Kitchen, patio, and garage.
The sonance box in question is a speaker distribution box, not an amp.  

Do do the RCA splitters have any major negative effect?

" His new house has 8 in wall speakers distributed throughout the house."

8 mono speakers, 4 pair stereo. or 8 pair stereo? 

"using the pre-outs from the Marantz"

Stereo or A/V, and if A/V, main preout or zone 2 preout?

Any way to control volume of individual rooms?

"Do the RCA splitters have any major negative effect?"

I would be more concerned about the speaker distribution box. Some have as much as a 50% power loss. Do you know the model number of this box?