rel with monoblocks

@maxoman1 

I know this is an old post, but in case others come across this post. I just purchased a single  Rel 212SE and will be using them with (2) Mcintosh MC601 mono blocks (fully balanced) I will not be connecting them in the manor described above. Not sure if your amps are balanced or not or if that even matters but REL certainly discourages the practice. I plan to run the outputs form my processor to the sub, and keep things on the safe side.. its not worth causing any damage to my amps or the sub. I have a rule. If the manufacture of the product warns about a connection type I typically will follow their advice. Good luck with your Sub. 

I’ve never noticed anything from REL recommending NOT using the "high level" amp driven input, as that’s a major part of the REL mojo, "The Sound of Your Amp." Very high impedance presented to the amp’s output means the amp doesn’t care. I use 2 RELs getting the same signal (helps with some room node standing waves it seems) and with proper placement and level they’re great sounding. One hot lead to each terminal (or each positive on a mono amp) and one to a negative lead...I doubt that would damage any amp. http://www.musicdirect.com/documents/pdf/ARELR218.pdf

The REL support pages specifically recommend to use the low level inputs with monoblocks and a single REL sub:

Monoblocks (1 REL) Connection Method
"It is not recommended to use the High Level cable when connecting a single REL. To achieve stereo input to your REL you will need to use the Low Level input. Please see our Low Level input guide."

If 2 subs are used with monoblocks REL revert to the high level speakon connection method.

I use the low level connections in for my setup and it integrates fine. Some users have apparently compared the Speakon to low level connections and prefer the later. Like most things it's probably system dependent.

https://relsupport.zendesk.com/hc/en-us/articles/115004649108-Monoblocks-1-REL-Connection-Method