I am driving my REL with the second pair of speaker jacks on my Cyrus integrated amp. I used this sub in another system via RCA with OK results but honestly after hooking it up via speakon connector I think it sounds better. I couldn't use it speaker level in the system it was in , but I really think these subs integrate well with speaker level input. My second system has never sounded better.
I think the only amps you can not do this with are true balanced differential output amps