I’ve got a Sony UBP X800 (I think its called) – it’s a UHD blu ray player and I have connected its SPDIF output to a digital input on my 272. Its also connected via HDMI to the TV (a Samsung 43 inch 4k telly), and the optical output from the telly is connected to one of the optical inputs on the 272. I have a small problem which is when I switch the audio to the SPDIF I get occasional clicks on the audio. These are not present when using the optical.
Any ideas how to stop the clicks? Is it noisy mains? I think the clicks are correlated with things like the central heating switching on. I understand mains filters are a bad idea, so any other ideas?
Generally speaking - found this rather good explanation:
The clicks you’re hearing are most likely the result of an asynchronous clock problem. The timing of the individual samples in a digital audio signal is governed by what is called the ‘word clock’. S/PDIF and AES-EBU signals both carry an embedded word clock, and the idea is that the device receiving the signal uses the embedded clock data to accurately synchronise itself to the source, and thereby receive and decode the digital signal correctly.
In your case: why do you need two digital inputs from the same source?
SJT, as Adam has explained above, the clicking can often be down to a synch issue, but can also be down to other factors too. TVs often float at half mains potential and will try to find any way to earth - often a problem with a properly earthed Naim system connected. If you disconnect the Sony UHD player from the TV does it still happen?
Sorry for the delay in replying (work and mending the washing machine got in the way) - I have tried and observed a couple of things
Disconnecting the TV from the BD player (i.e. unplugging the HDMI lead) still results in clicks
I think there is strong evidence that it is spikes on the electrical supply from other devices causing the clicks - it seems a click is caused when the central heating or fridge switches on. Last night, when I switched on the light, the 272 was set to the SPDIF input the BD player is connected to, and switching the light on caused a click.
I want the SPDIF output as well as the optical out of the TV because I want to play BD audio discs with the TV off - its rather distracting to have it on when music is playing.
I don’t have a dedicated mains supply for the stereo - its rather difficult in my house.
I think its either a mains filter on the BD player (which I understand is not a good idea for the audio gear) or to put up with the clicks.
Do you still get these clicks when the system is in standby ?
I had this problem. Intermittent clicks that were more noticeable with the telly off and amps volume turned down. I swapped out RCA SPDIF for optical between the Sky box and NDac and still had them now and again.
After thinking this through, I have all AV gear plugged into a decent Russ A simple unswitched distribution block, with the Unitiserve power cable supplying. This has cured it for me. So a feed that’s ferrite protected and separated from the system, must mean it was something to do with my system being more susceptible to high frequency noise perhaps.
A click is more likely to be an issue with errors, rather than SPDIF transport clock synchronisation in my experience. I would check the SPDIF interconnect… is it a 75 ohm impedance lead or just a regular phono lead, the latter may be more prone to errors… Also does the 272 say the digital input is locked or not… if locked the receiver has synchronised to the transport clock.
The other issue might be errors due to lack of output galvanic isolation, so there is an earth loop, but I believe most Naim digital inputs are galvanically isolated, so not sure this should be an issue with Naim, but don’t know for sure the 272 inputs are isolated. Can you try Toslink instead, do the clicks still persist?
Thanks Tobyjug and SIS for the replies. Some answers (where I can - I can’t test things out today because I am not there)
The digital cable is a Chord C-digital, which I think is a proper 75ohm lead. Interesting comment about whether the 272’s input is locked - I haven’t heard of this before so I will check.
I hear no clicks on toslink - the telly is connected via toslink to the 272 and I haven’t heard any clicks here.
I think the clicks are mains spike related. They are only on the digital coax input to the 272, and happen even when nothing is playing so I think its something to do with spiky type noise on the mains - as mentioned above, I had the blu ray player digital coax input selected in the 272 with nothing playing and switched on the light in the room and got a click. I have also heard the clicks when the central heating switches on. (Sorry, perhaps “click” is misleading - its more like a glitchy noise.)
I think the comment about the unitiserve mains lead is interesting. I wonder if it might be worth putting a ferrite block on the extension lead to the blu ray player and the telly to act as a low pass filter - any thoughts? (BTW 272 and 250 are plugged directly into wall sockets via power line lites. Telly & blu ray player are plugged into a cheap tesco extension block that goes to a wall socket in the same ring as the 272 & 250 sockets.)
Would the Russ Andrews distribution block be a power bar? I have a spare power line lite I could use to supply this, and put a ferrite block around it. The power bar looks well made and is reasonably priced, so I could spring for one of them and a few ferrite blocks. Any thoughts on this as a proposed solution?
Well I appear to have found a solution. When I had the clicks, the coax cable was connected to one of the RCA connector SPDIF digital inputs. Yesterday on a whim I tried other RCA SPDIF input on the back of the 272, and still got clicks. Then I tried the BNC SPDIF input on the 272. On this input there were no clicks, and I haven’t heard any clicks for over a day. I am using the same cable (Chord C-Digital RCA-RCA) and I am using the RCA-BNC adaptor that came with the 272.
No idea why this is. The only thing I can think of is that I saw a pic of the insides of a 272 and the RCA inputs are wired to the PCB using a couple of wires twisted together and the BNC input is directly on the PCB, so the RCA inputs may be more susceptible to noise. Just a guess. Anyway I am pleased I found a solution!
It could just be down to a poor fit of RCA phono plug to the socket. I can often get signal drop outs and clicks by manipulating certain coaxial s/pdif leads as the plug and socket make and break multiple contacts. It’s one reason why BNC is a far more effective connector here.
It would perhaps suggest the Blu-ray SPDIF output or possibly 272 RCA inputs are outside of impedance spec or at the edge of it. A phono connection is very unlikely to be 75 ohms characteristic impedance, so will encourage a reflection. Although typically this tends not to matter, but in your setup with your coax lead it may just be blurring the signal too much, and the BNC connection, which can be 75 ohms CI, is enough to keep in spec.
Glad you got it sorted… though I have a sneaky suspicion you will still be getting very occasional clicks…
Thanks for the explanation - I remember being taught about transmission lines and standing waves etc but that was long ago and I have forgotten it all. I haven’t heard any more clicks so far but I thought since I am using the RCA cable with an RCA-BNC adaptor that can’t be much good so I have bought a hopefully better coaxial cable with a BNC connector on the Naim end.
I have to say I am quite impressed with the BD player as a transport - I have used it for UPNP and now I am playing a blu-ray audio disc (see my post in the music on special offer thread - bargain!) on it via the coaxial output and it sounds great.