New guy here although I have owned Naim/Linn gear since the early 80s. I realize this topic has been covered in other threads, but I’m not sure those threads reached conclusions. I recently moved to a new city and my system Naim 72, NAP 250 with Gustard DAC started playing radio when no input was present. Of course the amp had to be on for this to manifest. Based on other threads I wrapped my power cords and grounded them to my power strip with a dedicated ground plug. This did not solve the problem. I then wrapped my speaker wires in aluminum foil and grounded them to the same ground plug. Bingo! No more radio and dead silence even with volume to max. Also, I worried the foil wrap might cause other issues. I have not noticed any increase in heat in the amp which I’ve read is often a symptom of too much capacitance in the speaker wires.
Hello,
what speaker cable are you using?
Certain types and banana plugs don’t work well with naim amps,
Need to find that foil hat of mine,
I knew they where real
We have a similar problem with our 202/200 system, that sits in the same room as our Celular Broadband router.
The NAC A5 cable is always picking up the pulses from the router.
We will be trying some Chord Epic X shielded speaker cables in a couple of weeks time to see if it resolves the problem.
There doesn’t seem to be a source component in your system! (Just a DAC, a preamp and a power-amp.)
A potential source of the issue is that it’s likely that the signal 0V isn’t connected to earth (i.e. protective ground) anywhere. In Naim systems this has always been done by the source component, and most DACs do not provide this connection. The lack of a connection from 0V to earth is often a cause of sensitivity to RFI and EMI.
Naim A4
Hi Xanthe and thanks for the reply. I am currently using my TV via Toslink to the DAC which sound amazingly good. I would think it is unlikely a Toslink connection would contribute to a grounding issue. And since I solved the problem shielding the speaker cables I feel like the problem is solved. But yes, since I bailed on vinyl/LP12, I need to select a new source. Various streamers are in the mix all which have I2S output.
In that case you need to check if the shell or the RCA connector on the Gustard is connected to the Earth pin in it’s IEC power connector. If not then you shroud arrange a separate connection from a 0V connection on the Gustard or the NAC72 to earth. This will improve the sound quality independent of improving the EMI rejection.
Am I simply connecting the shell on the Gustard RCA input to earth. If this is done on the board, do I risk a ground loop?
If it is connected in the Gustard DAC then yes you’d get an earth loop - you want precisely one connection from 0V to earth and only one.
If you have a multimeter, you can check that.
I did as you suggested. I ran a connection from chassis ground to one of the RCA shell inputs. I assumed since single ended shares a ground I only needed to connect to one channel. I then removed the aluminum foil from the speaker wire. The radio is back. I plan to get some better commercial shielding and use that instead of foil, but the foil confirmed my thought that the speaker cable is acting as an antenna. I did check with multimeter which also indicated no ground to the shell of the RCAs. Since I did not pick up a new hum I assume the Gustard was not signal grounded.
Fair enough, it really is getting in primarily through the speaker cables!
Just a thought…
How recently have the 72 and 250 been serviced (by an official Naim service agent)?
It’s the speaker cables, used to get it all the time with Naca5.
As has been said, it’s the speaker leads, or more precisely, how they are arranged. When I had the slack zig zagged and placed under the rack near the power amp, I picked up AM radio. When I coiled the slack somewhere else, it went away.
It makes a full circuit with the preamp so while taking out the pre-power connection causes the problem to go away and may make it appear that the problem is the preamp or source, it’s simply because you broke the circuit.
Slack cable very close to a 250 is actually notorious for this problem, as were 135s I have been told. When I had the problem, I could hear it in the next room with the door shut. I wasn’t using A5 either.
No coil. Longest cable is 16 ft fully stretched. The other is 8 ft. stretched. The channel with the longer cable has the louder radio. For 35+ years I left the A4 cables both the same length which has been a PITA. Only since my move did I decide to cut one of them. I hear no difference and the amp is not heating up.
I have owned this setup since 1983. The last time I had it serviced by a Naim certified center was 2012. I’m not allowed to say what has happened since then,although I can say without equivocation that it sounds better today than the day I bought it. It started on Linn Sara and moved to Kan and now powers Kudos X2s.
I have now done extensive research on earth ground and it’s role in an audio component. All evidence is that chassis earth ground is only there for safety and does not enter the circuit unless a short energizes the chassis which then blows the fuse. If this is true, the idea of bleeding noise into earth ground seems dubious. I even posed the question to CGPT and here is the reply. What am I missing?
"You’re exactly right. From a purely electrical standpoint, audiophiles are mistaken if they believe they can simply “drain” noise into the earth ground. Here’s why:
- Isolated Circuit: As you mentioned, the chassis ground in a properly functioning audio component is not directly part of the signal path. It’s there for safety and reference, not for carrying current.
- Noise Requires a Path: Electrical noise needs a complete circuit to flow. Just connecting the noise to the ground wire wouldn’t eliminate it. It might even create ground loops, introducing unwanted hum or buzz.
There are a few misconceptions at play in the world of audiophiles regarding grounding:
- Misunderstanding Grounding’s Role: Some might believe grounding actively removes noise, when in reality, it provides a safe path for stray currents and a reference point for the circuit.
- Placebo Effect: High-end audio cables or grounding tweaks might introduce subtle changes that some perceive as improved sound quality, even if the effect isn’t objectively measurable.
Here’s how to approach grounding in audio equipment effectively:
- Proper Grounding: Ensure all components in your audio system are properly grounded to the same earth ground point. This minimizes ground loop issues.
- Quality Shielding: Use high-quality shielded cables that prevent external interference from entering the audio signal path.
- Focus on Source Material: The quality of your music source (recordings, digital files) has a far greater impact on sound quality than esoteric grounding practices.
In conclusion, while proper grounding is important for safety and minimizing ground loops in audio systems, it’s not a magic bullet for removing noise. Focus on quality components, proper connections, and good source material for the best possible audio experience."