How to Connect a rel sub to a 200

Hello Naim talent pool,
I’m trying to connect a REL t7 sub to a 200 power amp and it degrades the sound with a loud humming sound. REL request a red cable to a positive output / a yellow to the other positive and the black to a negative - or unused as the case could be. I’ve tried
Several variations without success …could anyone give me an idiots guide without having to do a work around? I have a 202 pre and a hi cap in the same system but can’t see where that would cause any problems. Surely REL and Naim are compatible without complexity?
Many thanks to the team think tank on this.

The humming sounds is most likley caused by an earht / grounding loop.
NAP 200 has its own power supply. So does REL. It’s quite often that an earth loop happens, when two pieces of equipment, with their own power supplies are connected like that…

One solution - an isolation transformer, inserted into a signal path.

take a connection from the speaker terminals and feed it into high level inputs of REL…

( There is another thread - Supernait 3 and Y adapter and @xanthe has explained clearly )

will that be possible in your case ?

I see you have a Spendor Classic 100 - there shouldnt be shortage of bass - ideally…

Thanks to both yes I think it’s an earthing issue - just seems hard to fathom to resolve easily without buying more equipment. The spendor 100’s are not connected to this set up - they are magnificent if not ugly to hide ! I’m buying a pair of kef ls150’s to link up with the 200/202 combo in a different room / study hence the REL idea. The kefs sounded very good at the audition with the REL but I had no idea Naim would be so difficult to match.
I’m still chasing the manufacture as I thought they had worked something out with Naim on cabling.

As @anon93526344 says above - connect to the back of the speakers, not the back of the 200.

REL’s solution is to use a 3 wire cable with two signal wires connected to L & R signal, but only one 0V connection. REL suggest connecting this cable to the back of the amplifier, but this increases the HF loading presented to the amplifier; so for Naim amps the REL cable should be connected to the back of the speakers to avoid presenting a more difficult HF load to the amp.

Connecting to the speaker terminals of the amp or to the speakers is always going to be a compromised setup as the signal to the sub will then be influenced by the back emf generated by the main speakers.

See this:

Thanks gents sounds the way to go - the Rel cable provided doesn’t enable this as it’s sheathed but I will investigate with the Dealer about new cabling. By the way noting my system set up in the forum is old and should be updated … but not an easy task just to make my day!
Many thanks for the guidance it’s appreciated

You can simply remove the sheath and separate the three wires, assuming they are long enough to connect one to one speaker and two to the other.

Hello all

This was a painful exercise of countless hours reading the net but I think I have sourced a solution to linking a Naim to a REL sub without a major workaround - worth sharing and for those with engineering intellect it may be of interest to muse on…
Solution : ignore the standard REL connection instructions as it doesn’t work. Instead take the 3 coloured cables from the REL and connect to the Naim amp as follows >

  • Red cable connect to negative right speaker output

*Yellow cable connect to positive left speaker output

  • Black cable connect to negative left output

The above seems to reverse the issue arising from both having transformers and humming as the outcome is no distortion and a perfect tonal control with the REL.
There are quite a few posts in the forum on the various options to get this working but the above is simple, cheap and works without a work around. I understand REL also offer a blue line cable designed to improve clarity and imaging and it is supposed to work with Naim. Haven’t trialled it as the problem was solved for me but for those interested in an upgrade that may also be easy/brilliant and worth trying.
Thanks again for the suggestions and I hope the news I bring is a problem killer for others in the forum struggling with the same.

Yellow and red should be connected to positive, black to negative. With one positive and two negatives you will only get a signal from one channel.

By connecting to the speaker terminals you need to be aware of two things:

1 If the capacitance of the subwoofer cable is more than about 500pf, you will be degrading the sound to the main speakers.

2 The sub bass movement of the bass-mid cones of the main speakers will be affecting the output from the sub.

If you are happy to live with these limitation then fine, but you need to take heed of HH’s point that you need two signal connections (Red & Yellow) and one 0V connection (Black).

Probably not adding anything (much).

1 Like

How are you attaching the wires to the amp?

Thanks Xanthe

The end conclusion is as guided by the forum experts such as yourself and via Naim sources - “only connect via the speakers themselves.”

The sound proved to be imperfect if not frustrating via the amp as I found through playing for a bit longer that the sub woofer crossover helps but is only subsidising poor(er) quality sound than the non use. I think I got over excited by the elimination of the humming sound initially and a placebo effect kicked in.

Thanks to all who were involved with the conclusion.
Regards Rannochlad

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