Hooking up my JL sub

Yes. But a Line Out Converter might be a better solution. The LOC connects to your amps speaker out and drops the signal down to line level allowing you to use the subs RCA inputs. Parts Express has one for under $10.

Great idea. I like that better as the tonal characteristics of the Simauido W5 amplifier is not lost and both the Von Schweikerts VR4 and the sub will be in sync. Do I simply unplug the RCA inputs at the sub and let the XLR input on the mono remain on the sub when I switch Marantz to watch movies? 

@millercarbon. Thanks BTW. Stupid question: is there a decent grade LOC unit that you recommend? Also, a few I saw online have a bunch of color coded wires sticking out. Which wires connect to the R/L of the amp speaker output. 

@millercarbon. Thanks BTW. Stupid question: is there a decent grade LOC unit that you recommend? Also, a few I saw online have a bunch of color coded wires sticking out. Which wires connect to the R/L of the amp speaker output.

Hard as this is to believe this is one where quality does not matter- other than aesthetics, cheap looks cheap- you will never hear the difference. 

I had to learn all about this earlier this year when adding a distributed bass array. My tube integrated amp had no sub or pre out and the Dayton sub amps only accept line stage inputs. So after learning about this I made a simple mod to the amp, and with a couple cheap resistors converted one unused RCA input into a stereo sub out.

Again, because I know nobody will believe this, but go cheap, it just doesn't matter. Another one everyone loves to argue, but its true, don't need both channels because all the low subwoofer range bass is mono. So if you care a lot how it looks and are willing to mod then search for line out converter circuit or let me know and I'll send you the link. Otherwise buy the cheap one at PartsExpress.com

You do this and if I understand your system nothing needs to change, just connect the LOC to the speaker on the Marantz, leave the existing RCA connected to the sub but move the other end to the LOC and the sub will now work for everything.

Piece of cake.

Thanks for the info again.