PC+Caiman DAC = Clicking noise at right channel output

[Vincent Kars]

Hi,
It was mentioned in the thread that if one uses an S/PDIF from a CD Player, the 'clicks' do not pop. What's the difference between S/PDIF streams produced by a PC and a CD player? In the stream turned on and off for each track in case of a PC and constantly on in case of CD player?
/Dmitry

Correct, most drivers mute when the audio stops.
If I use the Realtek drivers, the audio is muted when playback stops.
If I use the Microsoft Hi Def drivers only, a constant stream of zero’s is send.
I can notice the difference because my DAC (Benchmark) mutes after 15 seconds of no signal.
In case of the Realtek, it mutes, in case of the MS drivers it stays on.
Of course like any well designed gear, it won’t cause any audible click when activated or muted.

[sdo_riga]

Correct, most drivers mute when the audio stops.
If I use the Realtek drivers, the audio is muted when playback stops.
If I use the Microsoft Hi Def drivers only, a constant stream of zero’s is send.
I can notice the difference because my DAC (Benchmark) mutes after 15 seconds of no signal.
In case of the Realtek, it mutes, in case of the MS drivers it stays on.
Of course like any well designed gear, it won’t cause any audible click when activated or muted.

So it appears some sources like Sony PlayStation 3, Realtek audio drivers, VIA Envy HD stop the binary stream through S/PDIF, when the playback stops, instead of sending a stream of zeros. I wonder what specification of S/PDIF lists as proper behaviour.

I would imagine that a bit stream has to be buffered as 16-bit or 24-bit words for actual conversion to analog. If less bits actually arrived, for example only 15 or 14, the conversion would still handle the entire 16-bit or 24-bit word, but create noise, i.e. 'click'.

Is it valid to assume that when the S/PDIF stream starts (or stops), the first N (or last N) bits would be used by the receiver to recognize and 'lock' on (or 'unlock' from) the stream? Does the receiver IC send output before the 'lock' occurs?

[Vincent Kars]

Part of the SPDIF protocol is a pre-amble taking care of the sync.
More details: http://www.epanorama.net/documents/audio/spdif.html

[StanleyB]

Might be worth reading about why there is a click at the end or beginning of a track HERE

[sdo_riga]

Part of the SPDIF protocol is a pre-amble taking care of the sync.
More details: http://www.epanorama.net/documents/audio/spdif.html

The S/PDIF does not seem to be the issue... What else could be the cause?

[StanleyB]

The S/PDIF does not seem to be the issue... Something in the implementation DAC causes the click then.

Have you read the article in the link I provided, or is your intention to keep banging on about DAC implementation?

[Reid Malenfant]

That's an awful lot to read & digest, why don't you suggest to the poor bloke which bit to look at so he can get an idea?

After all there are clicky bits at the top to direct you

[sdo_riga]

Have you read the article in the link I provided, or is your intention to keep banging on about DAC implementation?

Hi Stanley,

If you look at the timestamps of the posts, they are 4 min apart. It seems I was taking time to type my message while you were typing yours. So I did not see your post with the link before submitting my post.

I try to narrow down where the issue is. Can 3 different sources by 3 different vendors be faulty with their S/PDIF implementation? It's possible.

I read the link and do not see how it's relevant unless somebody puts the light on it for me. The text seem to make sense for 'clicks' within a track. However, I did not hear any clicks, while playing a material. And in the previous posts both Windows 7 'test' sounds and PlayStation 3 XBR menu sounds were tests besides musical tracks. And those system sounds are free from audible clicks I would say when played through other outputs.

Just to make sure we refer to the same... I heard clicks only at the beginning and end of ANY material. The sequence was:
- hit 'play'
- hear the click
- hear the material
- hit 'stop',
- hear the click.

If the material is free from clicks (i.e. system sounds on Win 7 and PS3) and S/PDIF has build in flow control markers, what causes the clicks at the start and the end of S/PDIF binary stream?

[Marco]

Hi 'sdo_riga',

Welcome to AOS

Could you please pop into the Welcome area and introduce yourself to our community by supplying your first name, system details and music tastes, as this is a requirement for all new members joining AOS.

Cheers!

Marco.

[sdo_riga]

Done!