2 X Rel Carbons Incoming. Advice on powering?

Just placed an order for 2 Rel Carbon Specials on sale for boxing week, to pair with my B&W 802 D2’s and my Gryphon Diablo 300 amp(with DAC). I have zero experience with subs but am missing the gruntier B&W 803 D2’s that I upgraded from earlier in 2022, especially in my open concept room with vaulted ceilings. Why did I just jump into going with Rel vs other options like JL? Firstly because of Rel’s reputation when used for music, and secondly because Rel was the best option available from a dealer that actually commits to 100% refunds within 30 days on any product, if you are not happy. I know Rel has their 60 day return policy if you buy directly, but my other Rel dealer that said they can’t do demos or returns said Rel’s return policy doesn’t apply to my country… So I’ll have to break in as quick as possible if it doesn’t sound great right off the bat, which most speakers do not.

Looking forward to all the soundstage and “helping all of the frequencies not just bass” benefits that people and reviews go on about.  One thing that irks me about my B&W’s is how laser-focused the sweet spot is.  Move more than 2 inches and things are the tiniest bit off.  Someone else with the next generation of my speakers posted that adding a single Rel helped with off-axis performance, greatly.  Hope I find that to be the case.

I only have one suitable location for them, on the outside of each main speaker. Which according to Rel is the best position when using pairs. I also purchased two Bassline Blue high level cables. Will be purchasing Audioquest Hurricane power cords soon and connecting both directly to a single dedicated 20A circuit. All my other gear is powered by my Torus RM-20, which is powered by a second dedicated 20A circuit. This configuration creates a leaner sound than my amp plugged directly into the wall but also much cleaner and more solidly formed, so the weight of the subs should really help balance things out and offer the best of both worlds.

I’d be interested to hear of others’ experiences with subs, in particular any experience in terms of how to best power them, whether two connected to a single dedicated 20A circuit is an issue, and whether anyone thinks a conditioner on the outlet powering the subs would help and be worth the investment. Also, are the Bassline cables worthwhile? I can always return them if not :)


One other thing, because everyone’s access to quality power varies.  As I mentioned my amp does sound cleaner with more solidity when plugged into my Torus RM-20 isolation transformer.  It’s very noticeable.  But definitely not unlistenable when connected direct to the wall.  This implies my power is moderately dirty, which is normal in an urban setting.  But, I’m guessing (or hoping) that the slightly less clean sound will matter less when it comes to bass frequencies, and that the added expense of a second RM-20 and power cord will not be needed…. Or, have others found that their subs sound noticeably better when connected through a conditioner vs straight to the wall?

I have pair of the Limiteds, and a pair of the Specials.  IMHO plugging directly into your dedicated outlet is fine.  And, yes the Baseline blue and highlevel is the way to go.  Start by turning the filter all the way down, and the volume very low.  Feather each upwards and stop or reduce when they become noticable and locatable.  I do not run filters on large floor standers like you own.  I would not consider another Torus for the subs.  Have you tried the speakers with less toe in?  I have owned several B/W Nautilus speakers and did not find them to have such a narrow sweet spot.

Nice looking subs.

Positioning and adjusting gain to blend will do more than any fancy cables or plugging it into an unnecessary conditioner. 

Directly into the wall with the cheap, supplied  power /neutirk  cables gets the job done in my setup. Fancy cables and plugging into a PLC is a waste of money to my ears.


I'd love to have 4 of those Carbon Specials.

+1, @fastfreight advise on how to setup REL’s and Baseline cables. Plug them straight into wall with high quality power cables (12AWG). If the bass gets too boomy or cause structural vibrations due to lack of acoustic treatments in your room, use a pair of Auralex ISO Series Subwoofer Risers underneath the subs. 

Thanks all for the excellent advice. @fastfreight , I have experimented a lot with the positioning of the 802’s, including toe-in. I found that very slight toe in from facing straight ahead improves how natural vocals that are positioned dead-center sound. But I found the sweet spot is like a laser point no matter how I have them toed in. The one thing that did improve is the sweet spot now degrades smoothly off-axis instead of being more “jumpy” when toed in more. Not sure how to describe it other than “jumpy” - it’s like it snapped into place or was bad just inches apart. Now, it degrades smoothly as I mentioned, but the sweet spot is just as pin-pointed. My prior B&W 803 D2’s that I upgraded from were not at all finicky like this. The image would follow perfectly a little ways left and right of the sweet spot. Then again, the 803’s didn’t image anywhere near as well as the 802’s do.

With the Diablo 300 you need to connect negative to ground, NOT negative binding post. Look at REL wiring diagram for differential balanced amps

@audiojan wow, really? Didn’t know that. I didn’t even realize my Diablo was a “differential balanced amp”.

While the Diablo has a ground connector, it is not documented and some industry folks I’ve spoken with suspect the connector is the ground for the phono card, not for everything. They also said even if they were wrong, it could be either signal ground, chassis ground, or all of the above. I could figure it out using my multimeter but I’ve misplaced it at the moment! I might have to ask Gryphon.

If this is in fact the phono ground, my Torus they the Diablo is plugged into has a true ground connection. Could I connect the negative lead of the Rel cables to that?

Update:  just watched the Rel video noting how to deal with the ground wire.  Big thanks for pointing this out.  Could have fried my amp!


“I didn’t even realize my Diablo was a “differential balanced amp”.

REL manual is very detailed on how to connect pair of REL to differential balanced amp. Plus, there are tons on video on REL site on how to configure REL’s into one’s system. If in doubt, send an email to REL support, they typically respond within 48 hours. 

You’re welcome. According to both REL and Gryphon, the ground post works for both the RELs as well as the phono ground. That’s how I have it all connected

+1 @audiojan My Hegel H30 operate as a differential balanced amp in momo mode and unbalanced in stereo mode.  My Rel S/812s hsve be be connected differently for each mode.  Hook them up wrong and you can watch all your speakers try to jump out of thier enclosures. You don't wsnt yo see it.