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Here's a clue...about DAC design


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Hi Gordon,

 

I'm a little confused about all the clocks in a DAC circuit. ie, If we are talking about the Oscillator for the Sabre DAC are all the clock signals in the entire circuit including input receiver are derived from the main clock? ie 80MHZ clock is recommended on the Sabre DAC

 

Thanks

 

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I agree 100%. Gordon & Pat make their interests well known whereas Peter has yet to say anything about his.

 

I dunno.........he has a link in his sig to a forum of his own. No idea what it is about. Maybe someone would like to give us a 25 words or less description.

 

Oops, for a minute I though Tim-Ashley were back :~)

Ok, I know what this is about now per email exchange with Chris. But Chris, this is not much what people can guess. This includes Telstar, who was supporting me here (and not the other way around).

 

Allright. So people, in general, are not allowed to tell about, state, judge products, when they have a financial interest themselves in such a product. This means earning money over it. My case : I am working on a DAC, soon going to market (world wide) and it is meant to be the best ever made. I don't like to tell too much about it because the kind of crazy specs are highly dependent on third parties and suppliers, and what was promised yesterday, won't be met today (people may know about my Fiirewire stories, which is just one example taking ages, and although I have (had) it all working, production is something else because of totally unreliable suppliers -> place an order, receive 6 months later, that kind of thing).

This is why specs change over time and the uselessness of even raving about it. But I'll give you one : no incoming jitter and only clock jitter. I have this working here for over 4 months, which doesn't mean it is production ready on that part. This by itself is related to galvanic separation which I want as a final feature, but I don't know how to do it without creating jitter. Yet.

 

Right. So Chris asked me to put something in my sig about it, and I guess I will. But, I actually don't want to because of reasons I just talked about. And if I don't, I am not allowed to write posts as done in this thread ?

Well, I couldn't have guessed that. But now I know !

 

Thanks,

Peter

 

PS: Pat, where are your 25 words ? I tried to find them, but I don't think they are there.

 

Lush^3-e      Lush^2      Blaxius^2.5      Ethernet^3     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

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"PS: Pat, where are your 25 words ? I tried to find them, but I don't think they are there."

 

Here are 25 of your own words, actually 22, that describe your new endeavor:

 

"I am working on a DAC, soon going to market (world wide) and it is meant to be the best ever made"

 

How about these for XXHE?

 

I keep tweaking my music player software, already on the market, meant to be the best ever, but not meant for Macs.

:)

 

clay

 

 

 

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Labby,

 

Using the internal oscillator on the Sabre is a bad idea. Also using the suggested internal oscillator with an 80MHz crystal is also not the best results. It is better to use a sync clock = to the incoming stream and not use the upsampling.

 

Remember the evaluation circuit for the Sabre for which you are talking is not the best design that is like the average design. The RMS noise of that setup will maybe on a good day reach close to 60% the capabilies of the Sabre.

 

Any real designer would look at that and say it's the eval, I can do a lot better than that and attach each problem associated to make it the best they could.

 

Companies at RMAF were saying we have the Sabre and we have jitter less than 1ps. Dustin was telling them no not if you implemented it that way.

 

Thanks

Gordon

 

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