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Old 2nd February 2004, 08:09 PM   #11
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Quote:
Originally posted by Peter Daniel
So, you mean adding an extra clock? But where?

the 8412 puts out 200ps of jitter, so that needs cleaning up.....

Ciao
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Old 2nd February 2004, 08:12 PM   #12
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There is another option too, if you don't think you'll get much for selling this DAC. You could use input receiver circuitry and connect to it directly TDA1543 chip. In this way you would have already half of the work done and possibly also input switching available.

I'm thinking about similar approach with my Audio Alchemy DAC.
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Old 2nd February 2004, 08:13 PM   #13
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Quote:
Originally posted by Guido Tent



the 8412 puts out 200ps of jitter, so that needs cleaning up.....

Ciao
You have reclocking in mind?
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Old 2nd February 2004, 08:17 PM   #14
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VCXO/PLL ?
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Old 2nd February 2004, 08:19 PM   #15
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Quote:
Originally posted by Peter Daniel


You have reclocking in mind?

ofcourse, you know me, nah ?

reclocking in my definition is retiming of existing signal. Generating a new clock is neccessary to retime the signals, and can be done using a secondary PLL circuit (with a LOW cutoff, unlike the 20kHz ion the 8412)

Most important is the clock that actually converts the words, but retiming of ALL signals entering a DAC chip is worth the trouble, like we did

http://members.chello.nl/~m.heijlige...tml/dactop.htm

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Old 2nd February 2004, 08:26 PM   #16
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Cool CS8412 DAC

Hi,
The CS8412 likes to be driven differentially and NOT directly from the transmission line.
So my interface with the AD8561 or Freds with 74HCU04 and 74HC86 comes to mind.
Also a low noise ANALOG supply for the PLL of the CS8412 helps as well as the Wildmonkeysects loop filter.
Also my Asynchronous Reclocker might help though I believe it is best to prevent jitter from occuring as with I2S Direct, omitting the CS8412, rather than to cure it with a anti jitter device such as the ASR or an extra PLL after the CS8412. Best replace the masterclock in the transport by a good one. I guess the ......
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Old 2nd February 2004, 10:24 PM   #17
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You might check this post I made in Chip Amps section about comparing two DACs: Exotic component choice for a GC

I'm not so sure anymore if ASR is something I would consider a must.
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Old 3rd February 2004, 08:09 AM   #18
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Question Simple DAC better?

Quote:
Originally posted by Peter Daniel
You might check this post I made in Chip Amps section about comparing two DACs: Exotic component choice for a GC

I'm not so sure anymore if ASR is something I would consider a must.
Hi Peter,
Any clue why the "simple" DAC is better?
I am glad doing one mod at a time......

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Old 3rd February 2004, 08:51 AM   #19
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Default Re: CS8412 DAC

Quote:
Originally posted by Elso Kwak
Hi,
The CS8412 likes to be driven differentially and NOT directly from the transmission line.
So my interface with the AD8561 or Freds with 74HCU04 and 74HC86 comes to mind.
Also a low noise ANALOG supply for the PLL of the CS8412 helps as well as the Wildmonkeysects loop filter.
Also my Asynchronous Reclocker might help though I believe it is best to prevent jitter from occuring as with I2S Direct, omitting the CS8412, rather than to cure it with a anti jitter device such as the ASR or an extra PLL after the CS8412. Best replace the masterclock in the transport by a good one. I guess the ......

Elso,

Ofcourse a one box design yields the best solution, but if we restrict to external DAC and exoisting interface we have options:

- The industrial way (yuck)
- Idem improved with either good PLL or ASR
- Place masterclock at DAC and feed back that clock to drive
- Idem but still use PLL, place VCXO in drive and feedback control signal
- use SRC

All have their pro's and cons. I am still not happy with ASR as missed samples give distortion.
New SRC's are improving so there is still hope. The main problem remaining is the vast amount of jitter that these devices spit out, so extensive reclocking of all lines is a must.

Ciao
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Old 3rd February 2004, 09:32 AM   #20
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Default wildmonkeysects loop filter

'3300 picofarad cap from the loop filt pin directly to ground'

Is this cap from pint 21 to ground or from pin 20?

Also is 0.22mfd same as 0,22uF?

Regards,
Bas
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