Word clocks, any experience?

[Reid Malenfant]

Having done a little bit of reading i think i'm beginning to understand why these word clocks can make a good bit of difference to reproduction of digital signals (in my case CD).

It appears that anything daisy chained in a digital system is going to receive & extract the clock from the data stream & this already has a delay due to extraction & cable length from the source & this is of course the dreaded jitter

An accurate word clock can syncronize everything as long as equal length cables are used from the word clock itself to all digital components.

Has anyone here had experience of using one of these? I can only ask

[Welder]

I’ve not tried one Mark but isn’t it a bit of an overkill for a single Dac and source replay system?

My understanding is they may be useful for controlling jitter in multiple processing system such a recording studio by acting as a master clock for multiple slave clocks but most Dacs these days have accurate enough clocks for jitter to be negligible.
If the incoming data is buffered and stacked and clocked out to analogue conversion by the Dac clock rather than the source clock then isn't jitter in the incoming data stream is rectified at the buffer
If jitter in a two clock set up is a problem then wouldn’t it make mores sense to just get a better Dac with a more accurate clock?
Idk, maybe the above is only relevant to USB data transfer.

Intersting though.

[Reid Malenfant]

Hi John, hope you are well mate

You should know i'll be going to a three point system, Krell DT10 transport, dCS Purcell upsampler & then to a dCS Delius DAC. That looks a bit like a daisy chain to me

I'm simply asking, i have no knowledge of these things myself, but from what i have been reading a word clock makes some sense. dCS actually sell one, the Verona

Now just because i have stepped onto the dCS bandwagon doesn't mean i'm a mug. What i'm wondering is if i can get my Krell DT10 modified with a superior clock & then buffer that & output it to the other kit?

There is method in my madness, maybe

[Welder]

Hey Mark, I’m good thanks

Right, I see Maybe if you’re going to have multiple clocks then there may be some benefit. I have no idea tbh. I’m just going on what I’ve read.

I must admit I get a bit confused by all digital ailments being blamed on jitter.
While it may be, from what I understand, a more serious issue using SPDIF it seems like well implemented USB data transfer reduces jitter to really negligible amounts and the problems in fact lie with the analogue stage which tends to get neglected a bit on a great many Dacs
Looking at various jitter specs for Dacs (if you can find them) and then reading what the experts write concerning what amount of jitter will adversely affect the analogue output. It seems that many USB Dacs achieve what can be considered as negligible jitter
The problem is, very few people have the equipment to actually measure jitter and any problems just get attributed to it

Idk mate. I remember when CD players came out and there wasn’t all this concern about jitter then. CD players are just a transport and Dac after all.
As soon as separate Dacs and computers joined in jitter was what the Hi Fi press used to slag computer audio off with. Strange really.

[Audiocom AV]

Hi John, hope you are well mate

You should know i'll be going to a three point system, Krell DT10 transport, dCS Purcell upsampler & then to a dCS Delius DAC. That looks a bit like a daisy chain to me

I'm simply asking, i have no knowledge of these things myself, but from what i have been reading a word clock makes some sense. dCS actually sell one, the Verona

Now just because i have stepped onto the dCS bandwagon doesn't mean i'm a mug. What i'm wondering is if i can get my Krell DT10 modified with a superior clock & then buffer that & output it to the other kit?

There is method in my madness, maybe

Hi Mark

Does the Krell DT10 have a word clock input?

If so you can use a clock sync generator to the DT10 and DCS DAC.

Cheers,
Mark

[Vincent Kars]

Sound on Sound has an article about master clocks
http://www.soundonsound.com/sos/jun1...sterclocks.htm

[Audiocom AV]

Sound on Sound has an article about master clocks
http://www.soundonsound.com/sos/jun1...sterclocks.htm

Thanks for the information.

This article does not cover the real issue of locking the source of the SPDIF to the receiver with a common clock.

[Lodgesound]

Hi there;

Work clock generation is fine except that you will need a very stable source for the clock itself.

In my studio I use a broadcast SPG (sync. pulse generator) to feed the word clock generator's reference input. The SPG provides a stable reference to 6 decimal places of colour subcarrier (4.433619 Mhz) and thus the clock is extremely stable.

In professional situations such stability is essential for maintaining absolute sync. across a huge variety of production platforms where a standard speed must always be adhered to - to be honest in the home it could be a little OTT however as you say having all devices locked to a common reference would reduce jitter to a minimum.

The cost of the above equipment on the second hand market is around £1000-£1500 depending on the type of SPG in use.

[Reid Malenfant]

Hi Mark

Does the Krell DT10 have a word clock input?

No, but i reckon it shouldn't be too difficult a modification to give it one Effectively it'd be a case of selecting internal or external clock, that may prove to be a tad simplistic though when it come down to it


Cheers for all the input so far guys I'm keeping an open mind obout it but i definately need to implement an external word clock if i use the Purcell to convert to DSD to feed the Delius. There is a difference between the clock in the Krell & the one in the Delius & this results in a pause in the proceedings every so often (10 minutes or so for a second) where it looks like the Krell plays catch up

I reckon going over to AES3 will eliminate that as the kit will be receiving the clock from the Krell & locking to it rather than having to run the Delius in master mode & having two slightly different clocks

[Lodgesound]

Can you not set the Delius to slave lock to the Krell?