Hum in AV Bypass mode between NVI and XS2

I am experiencing a pesky humming sound from my speakers while playing Bluray/Netflix movies from my Sony Bluray player that is connected to the NVI by coaxial cable, and from NVI to the XS2’s AV input by a DIN to RCA cable with AV Bypass mode on the XS2 turned on. The humming gets louder as the NVI warms up and louder still when something that sounds like a cooling fan kicks in.

I have tried routing the cable between the NVI and XS2 away from other power cables. It seemed to help a bit. I also tried to add a ground cable from the NVI to the wall but that didn’t seem to have any effect.

I see some ground loop cancellation solutions such as iFi’s GND Defender or DC Blocker that I gather would fit between the IEC power outlet of the NVI and the AC cable.

I would appreciate any advice.

Have you tried connecting the Sony to the N-Vi via optical? Give it a try and let us know.

The Sony only has a coaxial output. Should I get a converter?

The Sony also has two HDMI outputs, one for audio only. So HDMI to optical converter is another option….

I wish Naim would go back into home theatre products. Until today the N-Vi still sounds awesome.

If you disconnect the Sony from the N-Vi does the issue go away?

Yes, once the Sony is disconnected the hum goes away. I have another TV box connects to the Optical input of the N-Vi. It generates a very mild buzz but nothing like the hum of the Sony.

It sounds like the AV sources are causing the hum (not unusual). Can you connect to the TV and then send an optical feed from there? Keeping things optical is really a good idea in this sort of situation.

The TV only has a coaxial out. Looks like a Coaxial/HDMI to Optical converter is the only way out. It may still have a small buzz but at least it eliminates the hum.

Or try an earth wire.

Thanks for the suggestion. I have tried earth wires on the Sony, N-Vi and TV and they did not seem to have any impact.

I have ordered a HDMI/Coaxial to Optical converter. Will report back once I’ve installed it.

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Maybe read a good book :books:

I’ll be on my way

I’ve received and installed the coax-to-optical converter, which also happens to have an HDMI ARC input. So I connected the coax from the Sony Bluray player to the converter and ran an optical cable to the N-Vi. The result is much reduced hum but a buzz remains. I then connected the ARC from the TV to the converter and there was a hum. So it would seem that I am getting hum from both the TV and Bluray. So I disconnected the ARC. With this I have gotten rid of most of the hum but have to live with a mild buzz. It would seem that I still have a ground problem somewhere in my chain of systems but that will be hard to locate. But I can live with the mild buzz and I can enjoy movies now with a lower noise floor.

As the sound from the optical cable is less muscular than the coax, I will upgrade to a better optical cable to beef up the sound.

I have a similar issue with a Cambridge CXN. I use this as a CD/SACD player via RCA to my Nait XS3, and BluRay via HDMI to my Samsung TV via its connection box ‘thingy’ (with an ARC HDMI connection to my Arcam AVR20, which is itself connected via RCA to the AV input of my XS3 to drive the front speakers in a 5.1 setup. Phew). Anyway, I cannot have both the RCA and HDMI connected simultaneously without a loud and permanent hum. Disconnect either output and the hum vanishes. As I use it mostly as a CD/SACD player the HDMI is unplugged, but on the odd occasion when I wish to watch a BluRay then I’m on my hands & knees changing connections. Very, very frustrating.

This sounds like some kind of earth loop. I guess because the Cambridge is connected to both the TV and NAIT. Have you tried a ground loop isolator between the Arcam and the NAIT?

I’ve never heard of such a thing - I’ll research it. Thanks Richard

So, 5 minutes on Google later…

All the ones I can find seem pretty basic and very affordable - will one of these have any effect on the quality of the RCA signal?

Others have used them and they’ve given fine results. Start with something basic and if that does the trick then you can maybe upgrade to something more fancy, or els just stick with it.


A bit late on the topic…

It’s a ground loop hum that you are experiencing. Quite a common thing with audio equipment.

An isolating transformer is needed. It’s inserted in the signal’s path between a source and an amp. Typical price range: EUR 10-20.

Got one, £11 on Amazon. Magic. Don’t understand how, don’t care.

It’s easy actually…

it breaks the galvanic connection between the components, thus cutting out ground loops.