digital clock and converter newb

[rockstudio]

Can you actually build digital clocks and converters for pro audio gear? I have read some of these threads about clocks and converters and they just blow my mind! I have a pretty nice creamware a/d converter, but I would love to build one myself. Is that even possible? Does diy-ing an a/d make it more affordable? I have listened to Dave Hill and George Massenburg and others (apogee) talk about clocks and they all have a different take. But one thing is constant, all of their converters cost $$$$. what's the deal?

[rfbrw]

It depends on what you are after and what you want to spend.

[Guido Tent]

Originally posted by rockstudio
Can you actually build digital clocks and converters for pro audio gear? I have read some of these threads about clocks and converters and they just blow my mind! I have a pretty nice creamware a/d converter, but I would love to build one myself. Is that even possible? Does diy-ing an a/d make it more affordable? I have listened to Dave Hill and George Massenburg and others (apogee) talk about clocks and they all have a different take. But one thing is constant, all of their converters cost $$$$. what's the deal?

Hi,

Ofcourse you can build your own, but to build excelent stuff, one needs to know his subjects:

www.Grimmaudio.com

I am inerested by the way in the different views about clocks.

best

[Elso Kwak]

Big Ben has high jitter and high price!

[Guido Tent]

Originally posted by Elso Kwak
Big Ben has high jitter and high price!

Hey Elso

We agree on that !

Today I worked ona CD drive from a well known manufacturer. They claim to have discovered and solved the jitter issue starting from 1990. The drive sounds horrible, and the meaurements are truly yucky..... Not only the clock itself contributes to that, but also power supply and layout issues.

Yes, high priced too

Another integrated CD player uses a CD loader, takes of the SPDIF and feeds that into the DAC boards. Obviously the loader runs on its' own integrated clock, and the DACs on the recovered clock from the CS8414

You bet, ridiculously high prices here as well. How do I tell my customers: confused

So, there IS room for improvement

best

[rockstudio]

From what Dave Hill of crane song has told me, there is no standard for word clock. I worked in a studio with a crane song spider as the master clock source. We were plagued by pops in our audio from the console which was of course locked to the crane song, and we couldn't figure it out. I sent the crane song to the factory for testing, and of course it was fine. I called and talked to Dave and he was flipping out about how every company builds a different type of clock and then he spoke about even daisy chaining your word clock will offset your gear and cause other related issues.
I have never built anything digital. I know that to buy a good converter (a lot of pro use the Lavry blue adc, I have not listened to one yet) you have to shell out over 2k. For one pair. Is it possible to build a unit that compares to crane song or lavry or apogee for under $2,000? I want to know!

[Guido Tent]

Originally posted by rockstudio
From what Dave Hill of crane song has told me, there is no standard for word clock. I worked in a studio with a crane song spider as the master clock source. We were plagued by pops in our audio from the console which was of course locked to the crane song, and we couldn't figure it out. I sent the crane song to the factory for testing, and of course it was fine. I called and talked to Dave and he was flipping out about how every company builds a different type of clock and then he spoke about even daisy chaining your word clock will offset your gear and cause other related issues.
I have never built anything digital. I know that to buy a good converter (a lot of pro use the Lavry blue adc, I have not listened to one yet) you have to shell out over 2k. For one pair. Is it possible to build a unit that compares to crane song or lavry or apogee for under $2,000? I want to know!

Hi,

Ofcourse there is a standard, but that isn't good enough to cover all potential problems. Levels can be too low when terminated (twice), or timing / reflection problems can spoil the fun.

As always, the user of equipment needs to be aware of such matters, as manufacturers can't secure everything by design.

In our CC1 we implemented zero pahse difference between in and outgoing clock, made output impedance selectable and have some outputs of which the phase can be set to 180 degrees. These measures cover most applications.

best

[bocka]

Hi rockstudio,

building an analog / digital converter is not mor difficult than buildung a DAC. I don't know about clock distribution in professional equipment, but the signals for a typical audio ADC are the same than for a DAC. You'll need a masterclock (typically 256 * fs), a bitclock, (64 *fs), and a wordclock (fs). Maybe the wordclock and the bitclock can be generated from the fs by a counter / divider with a sync wordclock input (shouldn't be too difficult) but I haven't developed such a thing yet.

All in all I think you can build such a unit for about $500. On the other hand you'll need some hundreds hours of work to solve all problems. And thats why the units are that expensive.

[rockstudio]

Wow, so these digital devices must be extensively de-bugged and accurized. Oh, one of the phrases I was trying to think of earlier was Sync Lock Loop.
Guido Tent- what company do you work for?
thanks!

[Guido Tent]

Originally posted by rockstudio
Wow, so these digital devices must be extensively de-bugged and accurized. Oh, one of the phrases I was trying to think of earlier was Sync Lock Loop.
Guido Tent- what company do you work for?
thanks!

Hi,

www.TentLabs.com
www.Grimmaudio.com

best