Squeezebox Duet

[leo]

Hi Leo,

Thanks again for your replies and you're not crap at explaining; got another explanation I'm crap at understanding

When you said depending on the new clock, how do you know where it's supposed to go better ? For instance, the new tentslabs clock or the one from audio-gd ?

Cheers
Olivier

Hi Olivier,

Better to ask again than just fitting something if not 100% sure

I'd ask the place you buy the clock from just to be sure if it can run the Xilnix direct, with mine I basically didn't want it sharing the same inverter as the one used for spdif

Leo

[leo]

I assume the clock you are using has a build-out resistor, on its output.

Pat

Hi Pat,

Theres an output resistor on the clocks onboard inverter, It was all just a temp quick lash up tbh, I need to look into something better suited as a full time replacement
Was thinking of using a PFM Flea and simply adjusting its onboard reg to 3.3v to the XO

Leo

[MyNaim]

Hi Olivier,

Better to ask again than just fitting something if not 100% sure

I'd ask the place you buy the clock from just to be sure if it can run the Xilnix direct, with mine I basically didn't want it sharing the same inverter as the one used for spdif

Leo

Thanks Leo for the explanation; new clock is ordered, I'm really impatient to plug it.

Cheers mate
O

[MyNaim]

Tried the trick with a chip clock to see how a new clock can improve things. Went for the one from audio-gd and honestly I don't know whether the ones from burson or tentlabs are better but what I can say it's WAHOO !

And the bonus is that Kingwa (conceptor, seller) is happy to help and advise, very nice person indeed.

One advice, go for it. One of the best mod i have made so far (with a good linear PSU).

And of course, thank you to Leo for his wonderful work.

an happy man !

[leo]

Thats excellent Olivier, I'm pleased to hear it went well for you

I'm hoping to try a couple of other clocks at some stage, should prove interesting

[steveinspain]

Having just read through this entire thread I can tell you I understand nothing at all !
I can join 15mm copper pipe for central heating, but thats as far as my skills go.
What do you guys do when you finish a project, or do you never finish - is there always a next stage to try ?
I started reading as I am idly wondering about getting a duet - would you do this sort of work for a fee for me if I got a duet ? Are there people who do mods for a living to stuff like duets/sonos etc ?
Respect to all of you who know how to and then do these mods just to see what happens !

[leo]

Once you start to understand how things work and start to see how certain compromises can be improved, modding can become pretty addictive when you start hearing the improvements it also becomes quite satisfying, obviously theres a lot more to it than just swapping bits about.

I sometimes do mods for friends when I get time, at one stage it got a little crazy so I had to limit them, doing your own stuff means you can do it whenever its convenient.
If you can't diy there is places like Audiocom who provide a modding service, they give you options etc to suit your budget

[ar-t]

The answer is yes. How much? Well, we can measure the difference. Whether one can hear that or not, is another story.

Without going into too much extraneous gibberish, we have the use of something called a Wavecrest DTS-2077. It allows us to measure the amount of jitter on a signal. Its strong point is that it can separate jitter into its two main components: random and deterministic.

Random jitter is just what it is called. It is Gaussian in nature, and exists in everything.

Deterministic jitter is a bit more involved. To simplify things a bit, we can say it is predominantly correlated jitter. That is, jitter that bears a strong resemblance to the data stream itself.

In the Squeezebox products, (which are very good, especially for the price), the designers have to make certain compromises, to meet the price/performance goal.. (All products do, but ones at the low price end have to do more of it.) The main compromise is using a hex inverter, to function as 2 clocks, and the SPDIF driver stage.

So, having said all of that, one would expect to see deterministic jitter, and yes, it does exist. It is a tad higher than the random jitter.

Ok, the question you all want to know:

Does changing the external supply affect any of this?

Yes, it lowers them. Not a great deal, but we can measure a difference. Can you hear the difference? Probably. Maybe. I dunno. It depends. All very valid answers.

The other question you want to know:

If one separates the clock and SPDIF functions, totally, what happens to the SPDIF signal?

If you do it properly, the deterministic jitter goes completely away. The random jitter can be much lower, depending on the quality of the clock.

Hope this sheds some insight.

Pat

[leo]

Excellent post Pat thank you
Must be great having all that nice test gear whenever needed

[ar-t]

Glad it was beneficial.

It is nicer to do work for outfits that can afford a machine that costs USD 77K, with a USD 6K s/w package.

Ok, they bought it on eBay. Probably cost $12K, when all the costs are added up. I think the most expensive piece of equipment we ever bought cost around $2K. Thanks to the telecom industry imploding (putting guys like me on the streets), there is lots of good stuff to be had. Just takes money.

Pat