An issue connecting REL sub via Neutrik cable to NAP 155 XS

I’m wondering if anyone knows the cause for the problem I’m having: when I try connecting REL TZero sub to my power amp via Neutrik cable, once the amp is turned on there is a loud buzzing sound from the speakers. Since the amp has only four speaker jacks, I’m using banana extension plugs to connect both the speaker cables and the Neutrik cable. I tried two different types of extension plugs and both exhibit the same problem.

PS. I don’t have this problem if I connect the cable to the back of my speakers instead. I’m also fairly confident everything is wired correctly, as described in REL manual.

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Yep u can :paperclip: attach them at the back of speaker… I use naim but I also bought the naim bassline blue… N I never had hum with either cables attached at speaker

Ah, so Bassline Blue is the solution if I’m to connect the sub to the back of the amp? Yeah, I just found this online referring to older Naims (I purchased mine recently but it’s from the classic line): “These Naim units feature an unusual output impedance that is quite complex. REL arrived at a special circuit built into each NAIM cable that replicates impedance so that it is safe to run Bassline Blue”.

Wish that cable was less expensive - it actually costs more than the sub :wink:

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Talk to your dealer n see what he can do for u :wink: if u connect at the speaker end do u still get the hum… Also do u have an av amp cause u can run it… The lfe socket to Ur av amp n that might eliminate the hum

No AV receiver… It’s a small desktop setup running stereo from NAP 155 XS. From your answer earlier and from what I found online I concluded the hum is to be expected with my amp so I’m resigned to just running the high-level Neutrik direct from my speakers - works great this way. Getting a $500 cable is not worth it in my case… Thanks!

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You need a proper grounding for your subwoofer.

I had the same issues when I was connecting the SVS SB1000 to my 5si. I fixed the very same cable and eliminated the hum.
With time I found one more solution - to sell the subwoofer :face_with_head_bandage: Not because of hum, but because I decided to live without the extra bass.

This is something possibly to be expected if trying to run a sub from a high level connection straight off the back of a Naim amp. As you have found, the solution is to run off the connections at the back of the speakers. That way the amp doesn’t “see” the sub cabling and you avoid any potential upset.


Use the Rel Bassline blue cable that is special for Naim. It is that simple.

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