Rel sub

Yes, I use a single Rel T/7x with mono blocks. My hybrid mono blocks are balanced (+/- referenced to each other and not to ground), so I connect as shown for “Differential (i.e. Fully Balanced)” in the accompanying Rel booklet: Yellow connects to left + and Red to right +. I connect the Black wire to a screw on the power strip which is earth/ground.

This wiring also works for a pair of balanced PP 2A3 amps I built with no global feedback and floating secondaries. However, to eliminate hum with these amps I also had to connect both secondary commons to earth/ground via the same screw on the power strip.

I can’t say if this wiring works for all mono block amplifiers, but it works for me. You may have to experiment to get to get the lowest noise and functioning connection. The Rel documentation says that not connecting the Black wire may work better for some implementations.

Thanks, I'll check it out.

I'm pretty sure Rel recommends using two sub woofers if at all possible They both eliminate so many room issues especially with a two channel stereo system I have two subs along with my tower speakers that have built-in powered sub woofers

There is a really good series on YouTube called " Subwoofer 101" and it covers all aspects of sub woofer setup and he swears by having two sub woofers 

I may have to go with two. Thanks

Why is a single powered subwoofer getting involved with the mono amplifiers?

I have a single powered sub and simply Connect the rca cable to the back of it.  My sub has volume and crossover settings on the back. It's a b&w asw 2000. 

Newer subs require Wi-Fi access to adjust them which is troubling but it's the modern age I guess.

I use the sub output from the processor I have.  My main speakers when I use my preamp for two channel listening don't use a subwoofer. Not really needed.