I own a JR model 8T. I had the same type of issues as you. Having contacted REL, I was told to hook up the system essentially the same way, yellow on the positive left, red on the positive right and the black to the negative ( neutral) of the red channel. This seemed to be ok. However, after I had my amp modded by Jeff, I asked him about this and he suggested that we add a ground connection at the chassis of the amp...which he did. I now utilize the ground connection for black, and the red to right, yellow to left. You might want to send your amp back to Jeff for him to do the same thing. Not sure I would want to loosen a screw of the chassis as Jeff suggests. Nonetheless, I think Almarg's advice is also correct. |
@ricred1 I’m not so sure that the compatibility issue with REL subs and balanced differential amps isn’t well documented. There are quite a few posts on this forum and others about the issue. REL themselves now has a helpful video on their web site about hook up protocol.
I run dual REL subs with my Jadis mono blocks, there were also some issues to hooking up those as well. I ended up having two connector cables custom made by Signal cable. Took me months to get the blend correct, and last night I noticed that my left subwoofer seems to put out a lot less output than my right...not sure why this is the case, but more experimenting to find out what’s going on. Sometimes these subs can be a royal PITA. |
In the past whenever I have contacted REL, i have done so via e.mail. They have always responded fairly quickly to all of my inquiries and questions.
The addition of another REL should give you a nice boost in SQ, albeit with a lot more set up time involved and experimentation in positioning, x-over, and volume settings in order to get the blend to be invisible. It took me almost two months to get it right...and I am still making very minor adjustments even now!! Two subs are more than twice as difficult to dial in than just one...BUT the effort will be worth it. |
@ricred1 So, REL are suggesting that you run a ic from your LFE on the sub to your preamp? I guess that would ground the sub, but I wonder if you also wouldn't potentially create a ground loop?
As I stated before, the ground connection that Jeff added for me on the back of my amp is the way I would think is the most effective way to get this accomplished. |
@ricred1 I think the blend is where it’s all at. The fact that the subs take their signal directly from the amp in the high level set up is what has distinguished REL’s for me over the years. REL used to claim that this was allowing the sub to more carefully track the signal at the amp end, not sure if they still claim that anymore.
Your dealer is possibly wondering how to connect the sub ground wire to the amp chassis...as unlike many other amp manufacturers, Jeff chooses not to include a separate ground connector on his chassis. If you look at Lamm, Pass and others they do include this. Nonetheless, as I said before, Jeff is willing to add this necessity ( which I believe it really is) to your chassis.
|
@ricred1 By summing the red and yellow wires together and using the black wire to negative you are only getting the signal from one channel of your amp. This is the way that I connect my dual subs...one per channel! But if you connect just one sub in this manner, you are only getting the information from the channel that you have connected to. IOW, a mono signal to the sub in question. This doesn't actually solve your problem if you want to use just one sub and have it run off both sides (l,r) of the stereo amp. ( or left/right mono blocks). |
@ricred1 If you are not connecting the black wire, I would be concerned that you are not grounding the sub. I connect my subs with the red and yellow summed to the red output per amp and the black to the black output per amp. This is with dual subs and mono blocks. I’m pretty sure that way they are each getting a mono signal....left to the left sub and right to the right sub. The way you are describing your connection would indicate that you are only getting the mono signal from one of your amps to the sub...and not the summed stereo signal. |
@ricred1 Al’s comment above about the balanced aspect of your amp is correct. I use both a balanced output amp ( the Rowland) and a non-balanced mono amp ( Jadis), The points that Al brought up are 100% correct with the balanced design. Nonetheless, I think you are not hearing the sub in a way that would be beneficial with the set up you now describe. The sub is only receiving the mono signal from the left ( or right, depending on which mono block you use) channel.
Quick question for Al, if I were to hook up my two (2) subs to my Rowland stereo amp, would I actually utilize the summed red and yellow cables for each left and right connector and the black cable ( now two) for the ground connector ( that Jeff installed)....or leave those disconnected entirely? ( like what ricred 1 is doing).
|
Richard, I am not suggesting that having two subs is a negative issue. In fact, I believe that two subs is quite beneficial. The second sub allows one to not only have a sub dedicated for each channel, but also seems to help in taming various room modes. OTOH, setting up two subs is far more involved and time consuming than just setting up one. IME.
@almarg Thanks Al, I might at sometime in the future hook up my two subs to my Rowland. I am currently only using this configuration ( twin subs) with my mono blocks..and using just one of the subs when I play the Rowland.
|
@ricred1 BTW, replacing the stock power cord and better still, the stock connecting cable with a REL Signal cable is a BIG step up in SQ for these subs. I highly recommend the Signal cable that they will supply with the yellow and red cables summed for your mono subs.
|
@ricred1 Good move on the Signal cables. Signal make some excellent cables at very fair prices, imo. |
@ricred1 Richard, what made you pick the Carbon Limited vs one of the other REL Subs. The new S series seems to be where they are concentrating their line. The Carbon series isn't even on their web page, unless you do a specific search. Seems like they don't want to push that model. |
Richard, you ordered one cable or two from Signal? If you are running two subs, I would think you need two cables ( one per sub). Your post above seems to indicate that you ordered a single cable. |
@ricred1 Thanks for the update. How do you like the new Signal cables vs. the stock REL cable?
You make an interesting point about the high level vs. the low level input. I would suspect that the high level should always sound better, just as REL states, simply because the signal to the sub is exactly the same as what the main speaker sees from the amp. Question is, whether the REL’s active amp is modifying the signal in such a way as to somehow interfere with the signal...and as such you ( or anyone) prefer the sound from the preamp via a ic (low level) vs. from the amp via the Signal cable(high level)...could be. I will be interested to hear your thoughts.
Have to admit, that I have NOT actually compared the two ( high vs.low) BUT once again, I do see REL’s logic. |
Al, surely the more accurate the amp is, the more accurately it will pass on the signal...therefore what REL is basically stating is correct. Either way, I totally get the point that the subs see exactly the same signal as the mains in REL’s high level set up. |
Hi Al,
Get your point, but remember that the main speakers are seeing their signal from the amp...and not the preamp. So, regardless of how accurate the amp is ( or is not) the most accurate signal that the sub can see in relation to what the main speakers see...is from the amp. Which is what REL’s point is.
@jtcf I fail to see how the blend can be easier ( or more articulate) with the line level ( low) connection, after all, the subs are seeing the exact same signal as the mains in the high level set up. That is NOT necessarily the case with the low level connection. Therefore, it is REL’s impression ( and mine) that the set up is actually going to be easier with the high level...and the SQ will be improved as well. |
@ricred1 Agree. However, be sure to listen to both set ups. If the low level is preferred in your room and system, so be it. Everyone has a different set of preferences, and their rooms and systems are also dissimilar...therefore your result/favorite may be leaning towards the low-level input.
|
Interesting, I wonder what accounts for your findings? |
Richard, you are comparing the two hook up connections with the subs in exactly the same place in the room...yes? |
Also, while the two inputs use the same board, that doesn't mean to say that the signal that board receives will be the same...in regards to low input vs high input. |
Richard, If Jeff told you to use the low level input, perhaps he was suggesting that in order for you not to have a problem hooking up to his amp. That would be my impression. You must have told him of your issue with the hook-up from your OP. |
Richard, I think if you always have your RCA ic connected to your preamp, then you are always listening to the low level connection...by default. I am under the impression that the connection to the low level input is done by inserting the RCA ic and connecting it to the preamp. Regardless of whether you connect to the high level as well. IOW, you have perhaps ONLY listened to the low level connection for all this time!
Now that you have done away with the RCA ic, you are for the first time listening to the high level. ( Again you are not establishing a good ground, resulting in the hum!) Here's a suggestion.. hook up just one sub as I do with my Rowland. The red to right positive, the yellow to left positive and the black to either negative connector. ( Make sure the RCA ic is NOT connected). This should be tried with the original cable supplied from REL...NOT the Signal cable ( as presumably this was wired for a mono hook up). |
Richard, were you or were you not connecting your RCA ic to your preamp from your REL at the low level connection (LFE connection)? Because if you were, you are now activating your low level connect ( pushing signal as well as establishing a ground), I do NOT believe you can have both a high level and a low level at the same time...as I was told that if you do this, the low level takes precedence. |
Richard, I would defer to Al’s points..and therefore not implement my suggestion. OTOH, Al do you have any idea as to why my balanced JR model 8T has no issues when connected in the manner that i suggested? ( which also was the way that REL had suggested to me to do the hook up when I first acquired my sub).
I did notice that Richard turned down the low level connection...BUT I believe that the connection to the low level bypasses the connection to the high level once the RCA ic is connected to the preamp/sub. Since he had sound, I would suspect that the sub may have been out of the system blend and the mains were being solely listened to. Any other possibilities? |
Interesting Richard. I got the exact same advice from REL and then on a subsequent call was told that the LFE.1 channel takes precedence ( same as the low level connection). If it is connected via an RCA cable. The second adviser told me that i should just run a wire from the preamp to the REL chassis to establish just a ground and not an RCA cable...i did neither. No question that attaching the RCA CABLE TO THE PREAMP AND TO THE REL CREATES A GROUND. |
Richard,
Clearly the best ( and maybe the only way) to hook-up the sub to your particular amp is to have Jeff install a ground connector ( like he did for me). This is a sure fire way to success.
Since you like the low level connection, maybe sending to Jeff isn't going to be worth it....with all of the hassle that will involve. |
Al, unless I’m mistaken, Richard had Signal make him dual cables for dual subs...as such, I think that Signal ties the red and yellow cables together per cable. That is what they did for my dual sub arrangement for my dual cables. Therefore, each cable has a Speakon end at the sub and a red/yellow connector and a black connector ( at the amp end). |
