rel with monoblocks

I used a REL Stadium 3 with BAT VK-60s and it worked well. With one amp you connect the positive and ground leads and with the other only the ground.
Jeff

I have a REL Storm III connected to B&K M200's. My manual said to connect the ground to the preamp, but I found it works better to connect directly to the amp as Jeff says, EXCEPT - I think Jeff meant to say "With one amp you connect the positive and ground leads and with the other only the POSITIVE."

My amps sit about 6' apart, so I rigged up a harness to them, and connect the REL cable to the harness.

Hooked positive to each amp and ground to preamp chasis with a storm 3, worked fine,

i ran the ground to the pre-amp and split the cable...works fine..

I have a stadium II hooked up to two Cary Slam-100's and there's no problem. Some posters have said that two subs are better than one - and I have no reason to not believe them - but if you don't have sub set overly high and you're not sitting right next to it, low bass waves are remarkably non-directional and it won't sound like the lows are coming from the sub at all.
Start with one, see how you like it!

Sounds good. I just wanted to make sure I wasn't overlooking some special issue that the rels have, but it does makes sense that one can use it with monos. Thanks to all for your input.

I own a REL Studio II along with a pair of brand new Allnic M3000 Mono Block Amplifiers and was able to successfully hook them up to each other without any problems. The way I did it is as follows (and just to be clear, when I say right or left, I mean as you stand facing the speakers. So, "left speaker" means, as you face both speakers, it's the one to your left, etc.):

My speakers (Sonus Faber Electa Amator IIs) are approximately 9.5 feet from each other, with a fireplace in between them (any greater distance between your speakers and you will not be able to connect a single REL Studio II to your Mono Block amplifiers without a Speakon, High Gain Cable that's longer than 18 feet). That's because I do not believe in positioning a sub-woofer between speakers. It should always be behind either the left or right speaker; preferably the right one because in most orchestras, that's where the bass section is located.

Anyway, I placed each mono block on the fireplace hearth, just under 1.5 meters from each speaker's terminal connections. I then set the REL Studio II's right leading edge one foot behind the right speaker's cabinet and the center of the sub-woofer, 8.5 inches from the wall. To connect the sub to my mono blocks, I used an 18 foot Speakon High Level Input Balanced, (insert, twist and lock) Cable, most of which I was able to hide beneath a carpet.

At the other end of the 18 foot Speakon Cable, three, 36 inch wires with spade connectors emerge. They are red, yellow, and black.

You run the Speakon cable exactly between your two stereo speakers and then you take the red (positive) and black (negative) wires and connect them to the right Mono Block's positive and negative speaker terminals. Then you take the yellow wire and connect it to the left Mono Block's positive speaker terminal.

In this manner, you're integrating the REL Sub-woofer into the system's stereo signal. I have two (one left channel, one right channel) 7 meter Purist Audio Design Praesto Revision RCA Cables that run from my Allnic L3000 (formerly L4000) Pre-amplifier's right and left outputs to the left and right Allnic M3000 Mono Block Amplifiers' inputs.

Having the REL Studio II located behind and to the left of the right speaker gives me the very best integrated sub-woofer signal possible. I simply use the REL Studio II's Fine, Coarse, and Gain Controls to properly "dial in" the stereo signal coming from my mono block powered speakers.

Hope this helps. Let me know how you eventually hooked everything up.

Smw1950

To those that are now reading this old post, the issue with monoblock and dual mono amps is that the standard hook-up of the Rel subwoofers will result in combining the two channels of music (not just the bass) when connected the standard way (per Rel's stereo hook-up in the manual).

This means that if you loose the stereo performance of the speakers as the hook-up combines the two channels. It is amazing how many systems I have seen with Rel's where the owners have done this and do not know it is occuring.

This is the case with the hook-up instruactions immediately above (SMW1950) has the same signal now going to both speakers (whatever signal is just supposed to go to the left speaker has now been mingled with the signal to the right speaker and this combined signal is going to both speakers). So in actuality, he is running a pair of mono speakers with a sound stage that is always centered (outside of the impact of the subwoofer being off-center).

I have spoken to Rel (distributor) about this a few years ago. You really have three choices with the specified sub:
1: use a preamp out to the sub
2: connect the sub via the speak-on to only one channel (right is recommended)
3: run two subs, one connected to each amp or channel (in a dual mono designed amp).

I have run both 2 and 1 subs with various mono and dual mono amps (Levinson, Krell, BAT, Pass, etc. . . ). Many two channel systems do not allow you to make this determination (that the channels have been co-mingled). However, if you have a pre/pro, hook that up to your mono (dual mono) amps and go to set up the speaker sound settings and you will find this to be the case (for example, when just the right speaker is supposed to emit its tone, you will find the tone is also coming from the left speaker! and vice versa). Disconnect the sub's speakon cable and this will change and perform as it should (ie. just the sound will be coming from the right speaker).

Again, lots of systems with Rel subs set up incorrectly and the owners don't even know it!

This means that if you loose the stereo performance of the speakers as the hook-up combines the two channels. It is amazing how many systems I have seen with Rel's where the owners have done this and do not know it is occuring.

This is the case with the hook-up instruactions immediately above (SMW1950) has the same signal now going to both speakers (whatever signal is just supposed to go to the left speaker has now been mingled with the signal to the right speaker and this combined signal is going to both speakers). So in actuality, he is running a pair of mono speakers with a sound stage that is always centered (outside of the impact of the subwoofer being off-center).

This is simply incorrect. With the red wire connected to the Right amp + post, Yellow to the Left amp + post, and black connected to either L or R - post (or any other ground point in the system) it's not possible to combine L and R channels in your amp. I have mine connected this way and am positive I have not lost stereo out put from my speakers.

One qualification: Fully balanced amps can't necessarily be connected this way.

Bdgregory, I have hooked it up exactly as you have suggested, both with two mono amps and with dual mono/dual differntial stereo amps and the end result has been the same for me every single time - that is crossed channels (ie. left signal also going to right speaker and vice versa).

The mono amps that this has occured with were BAT VK 60s run as mono amps and Channel Island mono amps. The dual differential amps have been Krell FPB 200, FPB 300C and Levinson 331.6 with all of the above (except possibly the CI amps) running in balanced mode. I have the Storm 3.

In all of these cases I ended up just connecting the sub to either the right channel or right amp. This corresponds exactly with what I was told on the telephone during two separate conversations with the Rel distributor (Sumiko I think, but am no longer 100% sure on the distributor name).

ok, I understand. Indeed not all amps are the same. I knew fully balanced amps present issues for the Rel (and not all fully balanced amps are the same), and it's apparent your amps do likewise. My amps are mod'd B&K M200's and I have no issues with them. Same for CJ's I ran previously, and the Ayre V3 (which is a fully balanced amp but only required a different ground arrangement) worked fine as well.

Bdgregory, I had no problem with my Rel and my B&K 507 S2 or with my CJ 5-channel amp.

I think the Rel's are great Subs (regardless of price comparisons to others) and can most highy recommend them. It was disconerning to me when I would run into troubles with them crossing the channels. If not for the conversations with Sumiko?/Rel, I would have assumed it was my sub.

I am currently running stereo (non-dual differential) and with terrific results. Thanks for your advise as well as I know you are an experience and knowledgable Agoner and would encourage other readers to take your advice, but at the same time watch or test for cross-channel experiences as I have encountered. You may be 100% correct in that it may be amp dependent. I appreciate your replies so that other readers can get further information and understanding from two different people's experiences.

Has there been anything new on this  topic since 2010? I'm hoping to add an REL-328 to my current system which is running two (one for right channel and one for left channel) Marantz MA-500 monoblock amplifiers. Will a connection as described by ckoffend above work? Is there a possibility of causing damage to the amplifiers?
Thanks

@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