Subwoofer connection to older tube amp


I need to connect my Dominator 8 Sub to an Audio Research D-90 Amp and SP-12 Pre. The amp outputs only allow left and right bare wire speaker connections for different ohm ratings and I'll use the 8 ohm for main speakers.

Like most subs I'm afforded 2 pair of Left & Right Speaker Level inputs and 1 pair L&R Line(RCA plug) inputs and 1 pair L&R Line outputs.

Where would I hook the L/R from the amp to the sub? I want to use the set-up mostly for music but also for movies/DVD's.
jamesk58
Hi, original poster here.
Is it possible to use the same SW for an HT system and a separate audio system?

Still have the ARC gear for audio and was thinking of using the same SW for the HT. Is it possible to connect a single SW RCA cable to my HT and continue using the dual wire method for the ARC amp/pre? The SW supports both single RCA input and dual speaker wire inputs.
Of course not having both systems on at the same time.

Thanks
Jamesk58 - It would be a good idea for you to ask this question in a new post since the only ones who are seeing it now are those who answered your original question about the sub hookup.