Fizzing issue

System seems to have developed an annoying fizz on both channels - v low level, high frequency - almost like a transistor fizz. I have a 252, 250. dr, Supercap dr, NDx 2 and an XPS dr through PMC Fact 8s. All of the units are relatively new; the Fact 8s are about 9 years old. Any ideas on best way to isolate the units so I can define where the problem lies - or any idea of the cause? I leave the kit on 24/7.

Cheers and happy new year

I had the same issue when had powerline WiFi extenders connected. In case you have anything like that, would suggest trying disconnecting them.

Is the hiss still there if you disconnect your streamer?

Yes, it sounds like it could be some sort of interference. Ethernet over mains devices can definitely do something like this at their worst. Do you have any such things?

Thanks for the thoughts. Disconnecting the streamer has no effect. Richard, when you say ‘ethernet over mains devices’ what do you mean? Cables? I haven’t connected anything to the system since the cps dr a month or so back.

“Ethernet over mains” (or “ethernet over powerlines”) are little boxes with ethernet ports that you plug into mains outlets. They use the mains cabling for data transmission.

How is your Ndx2 connected? Which router, switch…do you use?

Thanks. Yes. I do have one ethernet over mains device but it has been there for a while. It doesn’t share a plug with any of the Naim gear which is mainly plugged via power lines or a hydra. The NDX 2 is connected into the hdd socket in the 252. The wifi is plugged direct from the BT hub into the NDX 2.

I had the same powerline ethernet over mains kit for ages and only recently it started causing issues. When I removed it, the noise disappeared immediately.

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Thanks. I’ll dig it out and see what happens.

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‘Ethernet’ over mains devices (a misnomer as they certainly do not conform to the Ethernet standard) works by transmitting a high level of electrical interference over your mains supply. This is so strong that it generally finds its way around all of your mains cabling, and quite often your neighbors too. The fact that your HiFi kit isn’t plugged into it directly doesn’t make it immune.

A “fizzing” sound, using a 250 might mean it’s time to have the 250 serviced and re-capped.
How old is your 250 and if or when was it last serviced? (Edit: I just re-read that they are nearly new)
Mine would always sound worse when initially turned on and slightly improve after a while. However, I have also heard mine (9 years later) simply sound fizzy no matter how long it was turned on.
Just a thought anyway.

Thanks all. Looks like it was connected to the ethernet over mains device. Shuffled a few plugs around and it cured it. Wasn’t the same socket as the Naim gear is plugged to but seemed to be causing the problem. Maybe my ears but seems to have improved the sound. The Addition of the XPS dr to the NDX2 is really paying dividends all round. Hearing things I never heard before - the overall sound is much fuller all round. Cheers


Just being plugged into the same house mains these things can reek havoc with sound. Pleased you got to the bottom of the problem and have received a nice upgrade too.

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