For REL setup experts
 

I've had a pair of Britannia B2s for several years and finally got an opportunity to secure a pair of 212SE for my 2 channel room :banana:. I'll get some pics up when I have everything cleaned up but here's a question I've longed to ask but never got around to really experimenting.

Most everyone knows that the Neutrik speakon connection is the preferred method according to the engineers at REL and I have no doubt they have done their homework. My problem (and this goes back to a Storm I used to have as well as the Britannias and now the 212SEs)......I get practically NO volume using the speakon connection. I've tried literally everything, it's not a room setup issue.....as soon as I use the line level inputs or the LFE input, they immediately come to life and I have to turn them way down. Now enter the 212SEs.....these things are huge and I was worried that I may cause structural damage :D if I didn't have them dialed in properly. It turns out the same thing....using the Neutrik connection I get practically no volume......I have the volume turned up about 5 or 6 clicks away from max and still it was very low and you could feel/see the cones barely moving. No volume problems with the low level inputs. At this point I have to wonder if it has something to do with the MC 402 amplifier since this is the only amp I've ever had with all 3 REL models.

I'm familiar with all of the hookup controversy but am sure that I'm hooking them up properly as the MC 402 is a differential balanced amplifier and that's specifically noted in the manual. The 212SE manual even warns that you may have to disconnect either the yellow or red lead in case the output was too high to dial it back a bit. Well that's certainly not the issue in my case.

I'm wondering if it has something to do with the autoformer or some design issue with the dual differential design of these McIntosh amplifiers? It seems like the RELs are not seeing enough signal out of the amplifiers outputs to drive the subs. Has anyone run into this or am I overlooking something very simple?

- Buck

Buck,
Congratulations on the pair of REL 212/SE. I'm seriously considering a pair of 212/SE's with my Tannoy Canterbury's and will be looking forward to your photos and listening impressions. Hope you get the connection figured out quickly. :thumbsup:

When I had the REL G1 I and 1.2Ks I connected it as the photo below shows. I did not have a pair of subs as REL recommends. You have to connect the "black" wire to a chassis ground screw. I have no idea why you are getting low output.

https://relsupport.zendesk.com/hc/en...y_Report_2.png

I spent two days last week auditioning Tannoy's with a pair of REL 212/SE's. I looked at the connection but not close enough to be any help. I do remember it was the SpeakOn connector but since my mind was on the Tannoy's I didn't spend any time focusing on the amp connections.

I previously had REL Britannia B2, B3, and R305 and can only offer some suggestions..........................

Did you test using low frequency test tones? http://realtraps.com/test-cd.htm
Did you try raising your crossover settings?
Did you try a different Neutrik cable?
Did you try the other channel amp connection?

Best of luck!
Ron

Jim - Yes, that's the exact way I tried with my Britannia B2s.....you had to attach the black wire to a chassis screw. They must have changed something with the design of the S series because in the manual, it specifically shows to wire them the way you have above except now it says to float or not connect the black wire to anything at all. I'm wondering if it has something to do with the fact I'm trying to run stereo (L and R) and not dual subs......I have no idea at this point? I just assume there has to some compatibility issue here because there is no way in the world a pair of 212 SEs should have that low of an output. I've done some searching on the web and it seems most people have the opposite problem and have to do something to lower volume output.

- Buck

.

Hi Ron, yes, I actually did all of those things...I have a Velodyne SMS-1 subwoofer management system that I use the mic for to see what kind of response I was getting (I just used the mic/software, the subs weren't going through the unit). I have tried the other things as well, I tried both the 4 ohm and 8 ohm taps on the 402 with no difference. The only thing I haven't tried is a totally different 2 channel amplifier...don't have easy access to one, I'd have to ask my dealer to borrow one which I guess is a possibility.

- Buck

Just a thought, how efficient are your speakers?

Average........4 ohm, 89 dB if I remember correctly but the speaker load should have nothing to do with the REL speakon hookup. Remember, I can hook them up to whichever tap I like (I've tried them all BTW) with the same results.

- Buck

I may send REL a tech support email to see if they have any experience with users and the McIntosh quad balanced power amplifiers. I haven't done any more experimenting today, but unless there is another way to achieve gain from the speakon hookup I don't know what else to do.

- Buck

I do hope you are able to come to an acceptable solution. I use a REL B1, one unit, and it blends beautifully with my Sf Cremona Auditor Ms. A true sw should be felt before being heard, part of the room pressurization they are designed to do.

Yeah, it’s a bit strange, I get plenty of very deep low bass as well as the “pressurization” that REL is known for using the low level inputs. It’s just that they insist that the high level input is the way to go so I really want to try it to see how well it works, I just always chalked it up to not having a “ big enough “ sub. Well with the 212SEs that’s definitely not the issue, so I know now that something else is going on.

- Buck

BUCK, here's more info from REL in case you didn't see.......https://relsupport.zendesk.com/hc/en...ced-Monoblocks

Ron

With 2 B2s you should have ample bass/sub-bass support regardless of input. This sounds like a crossover, amplitude or possibly phase issue. I've tuned in lots of RELs in my time and have owned B1s (having demo'ed B2s as well). You can definitely find a batch of settings that will work. Also, make sure the B2 is set properly to expect high-level input....the Mode selector switch for high-level input should be set to '1' or '3' for Line 0 degree or Line 180 degree phase depending upon your setup. It's also important to determine whether you need to go into the High-Level Balanced or Un-balanced Neutrik connector input. The volume setting is also a different dial (I'm sure you know this) for High-Level as opposed to Low-Level inputs on the B-series.

Sometimes there are connection issues with REL when connected to fully balanced, or dual differential amps. The issue is finding the correct place to ground the sub. Try connecting the blk. wire to chassis gnd. or to the gnd. side of your amp's RCA input. If these two locations don't fix the issue leave the blk. wire disconnected and run a separate wire from your amp's RCA gnd. to the sub's RCA input gnd. .

I know this is a bit of an older thread, but here's what happened......as soon as I got the D'agostino stereo amplifier in the setup, I hooked up the RELs the exact same way using their neutrik speakon cables. Clean powerful bass ensued! Absolutely no problems. I can only chalk it up to the McIntosh MC 402.......this is the only amplifier I have ever had (up until the S250) used with REL subwoofers and all of them had the same issue. They only think I can't figure out is that I've spoken to 2 dealers and other users who have never had any Mac issues with REL subs so I have no idea what the deal was. All I know is that with the Dag amplifier, there is no issue. Weird.

- Buck

For REL setup experts
 

Buck - not all McIntosh amps have the same output configuration. Your 402 like my 602 has fully floating transformer outputs that aren’t referenced to chassis ground anywhere.

So the REL speaker level hookup just doesn’t work in this case. It’s a REL design defect.

REL needs to use balanced differential inputs for their speaker level connections which would solve the problem completely and simplify user hookup. Other sub manufacturers do exactly this.

You’ve found a pretty high class way around the problem! :)

Tom

I'm not familiar with the grounding scheme of your new amp. Hope I wasn't too technical, simply put grounding is the key to proper operation. Some amps, like my Levinson, have two ground circuits, chassis gnd. and signal gnd.. Signal gnd. is 10 ohms above (higher) chassis to prevent noise from degrading the input signal. So I had similar issues. This is not a defect, just requires a different solution.

I would argue against a design fault. The fault is not including comprehensive grounding instructions in their manual. I'm confident a REL sub can operate correctly with a Mac. 402 using an alternate ground connection.

+1..

Call REL, they can walk you thru it...(to OP)

Since I don’t have the 402 it doesn’t matter any longer, but last year I did call REL....their response was that they had no idea so just use the line level inputs.

I helped a friend of mine hook up a 212/SE to his MC 402 and the final answer from REL was to use the low level input.

In their dozens of detailed online support pages:

https://rel.net/how-to-connect-my-rel/

they do not have a way to connect a fully balanced and floating amplifier to their grounded high level input. So even though they clearly indicate the low level connection is inferior, that's the only choice that works with the likes of the McIntosh MC 402 and MC 602. Other McIntosh amplifiers may be different and may work - I just don't have personal experience with them.

Tom

Your comment is 1/2 correct, as I stated earlier connect the blk. wire to the gnd. side of a RCA input on the amp or run a separate wire from amp RCA to sub input RCA. This works perfectly and allows use of the Neutrik connection. I have done this on several REL subs without issue. It is a shame REL has not discovered this and provided it to their customers.

Tried that - didn’t work as the speaker outputs on the 402 and 602 float wrt chassis and signal ground.
To their credit REL does describe the method you suggest in their extensive online hookup info. Also in REL’s defense their subs will work with most amps out there. And the low level connection always works. :)

Thanks for the great information Tom, I figured that some issue like that was always the case. The thing that threw me was that when I talked to REL, of course they mentioned that they've had tons of McIntosh/REL users with no issues. Whoever I talked to at their tech support probably didn't drill down into the fact of the specific characteristics of the MC 402.

- Buck

Rel
 

Yes , it appears to be an unusual situation with these particular McIntosh amps. It seems that the autoformer is being used as an isolation transformer. Common in surgical suites and boats. Seems unusual for a stereo.

So, in this case there is really is nowhere to connect the black wire to get a reference ground voltage - there is no such path.

Correct in this situation the blk. wire is left unattached. My system is the same. It requires a separate wire between the amp or preamp RCA gnd. to one of the sub RCA jacks. The red and yellow are connected to the amp's right and left speaker binding posts.

IF anyone is still reading this, i just received this email from Chuck at McIntosh today - seems to confirm everything i just read above:

Hi David,
Yes, the MC402 is Quad Balanced and can not be run with the negatives tied together, do not use the REL speaker level connector.

Connect low level from your preamp to the REL RCA inputs.

Just going to jump in here. Does the mc462 have the same issue? Also please confirm if the rel red and yellow wires can connect to open binding post on the amp that are not used by the speakers? Would there be any change in how the sub interacts doing that, I.e., various ohms?

For REL setup experts
 

I owned a pair of REL B2 subs and connected the both of them to my MC402 for years and then a pair of MC501, and a pair of MC2102. It was only very soon before I sold the subs did I find out here on AA that I had them hooked up incorrectly. I thought my only mistake was not knowing that a differential amp is synonymous with balanced amp, or in the case of MC402, quad balanced. Turns out even when I changed the connections to the differential config, I was still wrong since the grounding scheme of the 402 isn’t sympatico. I guess i was lucky nothing happened to my gear as a result. At the time, I did not experience the low volumes that Buck described with the caveat that those systems were installed in a really small bedroom that was my dedicated listening room. BUT I do remember being floored at the difference when I bought a single JL f110v2. Massive improvement versus the REL. Now I know why!! Live and learn.

For REL setup experts
 

I directly asked REL via Facebook a few months back, they were quick to answer. I believe it was John Hunter responding. Here’s his take on adding either a pair of 212/SE or G1 mkII to my Dynaudio speakers with McIntosh MC601 monoblock amplifiers, in the context of a multipurpose 2 channel, surround sound, theater environment .......

“Hi Jason, and thank you for the reach out--The 212/SE will work brilliantly in this application, whereas the G-1 MKII a. will likely present space problems due to its greater depth and b. for this sort of multi purpose system, the 212 is in its glory.

As to connectivity, I will note two things. First, we have ZERO issues connecting to McIntosh Quad Balanced stereo or monoblock amps including the 402 model. What that style of amp requires is a proper ground, nothing fancy. Here's a link to the connectivity page on how to properly connect to MC601's--the 402 is the same but the little screw on the chassis is located very slightly differently. Because these are balanced amp designs, the "ground" tap on the rear is NOT ground at all. The solution is to locate ground, which in the case of all modern McIntosh amps can be found somewhere on the shiny chrome back panel. Here's the link and thanks again for the question.

Remember to configure your AV processor for Full Range on your main channels (we do so for ALL channels except Atmos which generally cannot be set to Full Range) if you intend to use both High Level and .1/LFE and remember that neither Marantz nor Denon recent offerings allow one to do so in theatre (but CAN be configured to do so for 2-channel music reproduction).”

Another key point in the linked article is they warn not to connect a single REL sub to a monoblock amplifier. Always use pairs of subs for monoblocks.

https://relsupport.zendesk.com/hc/en...ced-MonoblocksAttachment 59869Attachment 59870