Thanks to all for your support. So. I tried the Rel Naim Bassline Blues on the 250 non dr amp input first and drove it pretty hard for about an 1/2 an hour, that’s when I noticed the 250 was getting hot ! 
Something that has never had happened as long as I have had the 250 and I have pushed it hard.) So, Moved them to the speaker terminals the amp was still hot so I shut it all down. The subs did sound more natural and balanced when connected to the amp end. And not as natural or balanced from the speaker end. I would have thought that I would not have had the amp heating problem give the cable and sub match up. At this point I do know what to think ! Not sure if the Rel Naim cable are worth the trouble at this point.
Hi
The only other thing I can think of is … what speaker cables are you using ?
The early Naim amps are very fussy over type and length and even how they are coiled etc
Naim recommend their own cable NAC A5 that has the required inductance.
If you are using something else it may be they were marginal when being used previously and worked ok but once the subs were attached it has tipped them over the edge ?
Just a thought …
Hope it helps and good luck
I’m using naim SL’s on the 250-2 non dr. When I had the Nova and added the Sub the nova overheated. With the 250-2 It never even got warm, even when over driven, but with the addition of the Dual Sub I guess it’s to much of a load. I don’t know, I just know it’s disappointing !
Have you tried just running the subs off the speaker terminals using some basic low capacitance cable. We used to use Chord Leyline at the factory and it worked well. Discreet, easy to dress and cheap to buy too - you don’t need fancy cable for this connection.
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No, I haven’t. I just thought these Rel cables were set up for naim amps. But guess I will have to try something else. Thanks
Has anyone else had this problem with sub connection ?
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The stock cable REL supplies with the sub is perfectly fine. Run the subs off the speakers and be done with it. The stock cable is 10m long, I shortened it to suit my set up, 1.5m or so.
I’ve got a pair of T9is connected to the speaker terminals of ProAc D2Rs and got Design a cable to make up two 1.5m lengths of their standard cable with Speak-on plugs. Because ProAc use Mitchel terminals it’s easy to bare wire the subs and the WH Phantom bananas just pop in. No piggy back bananas needed and the rats nest of extra cables is kept to a minimum.
My amp is a 250dr and it’s really not bothered by the subs connected this way at all.
I also found that the amps built into the REL subs are actually really powerful so I only connected one of the cables. This effectively halves the output and makes it better to fine tune in my room. This is a snap of the set up.
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Thanks will do
Running a new T5/x off the back of my ( non naim) power amp. Just plugged the Rel supplied cable into the spare outputs on the amp, other end into the Rel. Just works, albeit Rel T5/x runs 180 degrees out of phase best.
Which ever position has more bass is the correct position. We all understand what Phase is don’t we?
My amp is a Balanced Bridge design. One can not use the speaker ground on the amp since it is active, not a passive floating ground. I have a ground connector on my Shunyata PLC, which I use. I believe the NAP 500 is also a Balanced Bridge design maybe @Richard.Dane would confirm…
The NAP500 is bridged.
I don’t know. I have made some changes to the system over the past month and have not been happy. Was not using it with the subs and I changed out a highcap-2 non dr and have been demoing a Supercap-2 non dr that i think may need service because with it on the 282 it seemed flat and over powering, it sounded louder, but all of the detail of the SL speaker cables was lost. I will say that the clarity volume and tightness of the bass the SuperCap brought out of the B&W CM 6s was stunning, but overall the total detail I had before I added it was lost. Once I stuck the Subs on with the Rel (naim) baseline blues it seemed to wake the whole system up. The sound stage that had disappeared wit the SuperCap opener up a very large part of the clarity and detail came back and the additional bass was welcomed even if not tweaked. The Rel upgraded cables have had a very positive affect and seem to have a bit of synergy with the SLs even if they do downgrade purity of the SLs somewhat because of the different quality of there bananas. At this point it’s all temporary until I decide what to do about the heating problem which tonight was half of what it was yesterday. So, not sure what I’m going to do right now.
That’s not necessarily correct… It usually is, but not always!
Right again. But can you sight any examples of Balanced Bridge amps that this would apply to?
Not specifically as the issue isn’t specific to bridge configuration amps.
However I can cite combinations of specifications of room / sub / sub positioning / speaker where this is likely to be the case (again not certain until tested!).
This sounds similar to a problem that I encountered with dual REL R-218s connected to a NAP140.
Try floating one of the REL high-level cable black leads. If you get a loud hum or any other abnormal sounds, then stop (have your volume on the low side when you first try this). If on the other hand, there’s no loud humming or other alarming noises, and everything sounds good, you can see if the overheating issue has been solved.
By the way, if your NAP250 gets hot, shut it off and let it cool down completely, before testing a different connection option. The temperature is probably increasing slowly over many minutes. And if you don’t fully cool down, before trying something else, it will be very difficult to determine if you’ve solved the problem or not.
It’s not strictly necessary, but a handheld infrared thermometer gun is quite handy in situations like this. I happen to have a Fluke 62 Max, but there are inexpensive ones available on the usual big river shopping site. With a thermo gun, you can completely disconnect the subwoofers, and run the system with music for an hour to establish a typical “normal” temperature. Once you reconnect the subwoofers, you can monitor the temperature, and then stop immediately, if it starts climbing notably past the typical temperature. Oh, and for consistency, choose one spot to measure, and then stick with that same spot for consistency. I just went with the center of the amp’s front panel, but it doesn’t really matter, as long as you then always measure from the same spot.
By the way, if you haven’t done so already, I’d recommend opening a ticket with REL.
Tamarin, Thank you for your detailed answer. I did call Rel and opened a ticket. The strange thing is that after I called them I noticed the 250-2 was not getting hot a little warm to the touch, but not hot. Also, I don’t have real high quality rack & for lack of space and some pieces are stacked in the small quarters of the rack so I rearrange the rack and it has seemed to have done the trick. I remember when I had a nova in the same rack and had one sub on it low level with a single rca audioquest boxer cable it would get really hot to the point of thermal shutdown so I tried adding a duel cabinet fan to the that shelf on the rack and just to see what would happen and it cooled it down 70%. I really need a better rack set up. A Fraim would be nice, but I can’t see that happening anywhere in near and maybe distance future lol.
The one thing I wonder with the Bassline Blue naim cable is with the the stackable jumpers. Because I know the silver of the black female jumper is no where near the purity of SL speaker cables, if in fact the Rel banana connection is some type of silver at all, so I wondered if it may be watering the SLs down.
Okay, good. Once you get to the head of the queue, REL has very good support. At least in my experience.
Nothing to do with subwoofers, but if it’s an enclosed cabinet style rack, you are definitely at risk for overheating. Especially with Naim amps, integrated amps, streamers and all-in-ones. Even the absence of a little bit of space above can cause components to run hotter (leave at least an inch or two of free space above such components).
Naim bananas are nickel, which I believe matches Naim speaker output jacks.
If I had SL’s I wouldn’t want to use stackable bananna plugs between them and the amp or speakers. Higher-end Naim cables (Highline, PowerLine and SL) are also engineered to reduce microphony effects. So putting something between them and their intended target might possibly compromise that.
But if I was using stock or basic cables, I wouldn’t worry about it too much.
Btw, the stock REL high-level cables are quite decent in my opinion. I just like to tin the exposed leads to prevent tarnish.
Thank you for the great advice again. It’s obvious you have had your experience with Naim and Rel Subs. Yes, when I received the BLBs it felt kinda strange, sacrilegious using SLs bananas on the ends of Rel stackables lol and I still not totally comfortable with the idea, but both cables do sound good together. The rels do add a lot to the CM6 S2 that I’m outgrowing. Have you ever used the non-Naim rated Bassline Blues with Spades on the speaker end of a Naim system ? Just curious because it’s seems not many people use the naim Bass blues with naim equipment.