Word clock input mod to slave my Philips CDP. - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 8th February 2004, 02:47 PM   #1
Lourens is offline Lourens  Europe
diyAudio Member
 
Join Date: Dec 2003
Location: Utrecht NL
Default Word clock input mod to slave my Philips CDP.

I have done a search (this forum and Google!) on this, but did not find what I was looking for. Can anybody help me, please?

I recently bought a second hand professional DAC featuring the possibility of word clock digital output. The manual says: it is intended to synchronise other equipment. It can operate in either Slave mode or Master mode. (...) In Master mode, it outputs a fixed frequency master clock, at either 44.1 kS/s or 48kS/s, for other equipment to lock to. This might go, for example, to a CDP. The CDP output is then locked to the DAC VCXO, and the DAC only has to decode the data coming in it knows the clock frequency. (...) We recommend this for CD players that can take advantage of it.

I should like your advise on modifying my CDP, a Philips CDD-882 drive (with CDM-1 mk II, and SAA7210/SAA7220) with a word clock input. Its a new-old stock machine with no mods what so ever.
1. Is it possible, and sensible?
2. If yes: how??
3. Should I also replace the existing CDP-clock? I want to improve on S/PDIF output anyway (with BNC out) and maybe an AES/EBU output. But is it logical to upgrade the clock since it will be slaved to the masterclock in the DAC anyway (which uses PLL and extensive re-clocking, by the way, so much so that comparing the new, virginal 882 to my old modified and LCClocked one, it is hard to hear the differences! These differences do not sound like jitter borne.)

I am looking forward to your expert opinions!
TIA
Lourens
  Reply With Quote
Old 8th February 2004, 03:30 PM   #2
diyAudio Member
 
martijn's Avatar
 
Join Date: Nov 2003
Location: nl
Lourens,

you ask if it is sensible to modify a drive,when in the same posting you mention the extensive reclocking of the dac that is to be used with this drive.
I doubt that messing with the clock will give any improvement.

Enjoy the music!
Martijn
  Reply With Quote
Old 8th February 2004, 04:16 PM   #3
Lourens is offline Lourens  Europe
diyAudio Member
 
Join Date: Dec 2003
Location: Utrecht NL
Quote:
Originally posted by martijn

I doubt that messing with the clock will give any improvement.

Enjoy the music!
Martijn [/B]
Martijn, what exactly do you mean with "messing with the clock". Replacing it by a (let's say) Tent of Kwak clock? Or to add a word clock input?

Mentioning the re-clocking as a possible explanation of the perceived small differences between my two CDD882's is really speculation from my side. About clocking the manual says: "The sample clock quality significantly determines the output performance of a DAC. (...) The active VXCO (one of two, L.) is synchronised to the clock signal extracted from the input by a PLL. This PLL is of a special narrow bandwith type that provides a significant degree of 'clock cleaning'."
That's is not the same as re-clocking, I guess... sorry.

Don't you agree with the recommendation (in the same manual) to use word clock synchronisation if possible? In the current situation, the DAC is slaved to the CDP!

grtnx
Lourens
  Reply With Quote
Old 10th February 2004, 03:05 AM   #4
diyAudio Member
 
Join Date: Oct 2001
Location: .
If want to slave the CDP to the DAC you would have to install a 11.2896 VCXO/PLL in the CD player and then lock this to the incoming wordclock. Alternatively, having installed the VCXO in the CDP, you could build or buy a wordclock generator and slave the DAC and the CDP to common clock.
  Reply With Quote
Old 13th February 2004, 04:55 PM   #5
Lourens is offline Lourens  Europe
diyAudio Member
 
Join Date: Dec 2003
Location: Utrecht NL
Default clock injection or sync link for external word clock?

In fact my dCS Delius DAC has two VCXO/PLL's (for 44.1 and 48kS/S related CDP-outputs). I certainly do not want to mess with that DAC.
However, it also has a word clock input and output. In master mode, it outputs a fixed frequency master clock, at either 44.1kS/s or 48kS/s, for other equipment to lock on. Specifications of this output: impedance: 25 ohm; sensitivity (unloaded): TTL; max. sample rate (slave): 96k S/s; connector: BNC.

After my first posting I've got very useful hints (thanks Martijn!) and did more homework, finding interesting options to slave a CDP, proposed by Peufeu (clock injection ) and LC Audio (Sync Link ). Both have their caveats, I learn from reactions on this forum.

So, I want to rephrase my rather confusing first posting to a very simple one:
What is the best way (if any) to slave my beloved Philips CDD882 to an external word clock, preferably using the word clock output of my dCS Delius?
  Reply With Quote
Old 13th February 2004, 06:42 PM   #6
diyAudio Member
 
Join Date: Oct 2001
Location: .
It seems to me, you have answered your own question.
Your CD882 requires at least 256Fs for its system clock. Your DAC produces a word clock signal, Fs. Clock injection and Sync Link invove sending 256Fs or greater. Therefore,given the need to derive 256Fs from the Fs reference, your only option is to install a clock multiplier of some sort e.g. a PLL.
  Reply With Quote
Old 15th February 2004, 09:16 PM   #7
Lourens is offline Lourens  Europe
diyAudio Member
 
Join Date: Dec 2003
Location: Utrecht NL
Quote:
It seems to me, you have answered your own question.
Nice. Wasn't aware of that

Quote:
Therefore,given the need to derive 256Fs from the Fs reference, your only option is to install a clock multiplier of some sort e.g. a PLL.
As you definitely have noticed, I am just a stupid beginner, so I have to ask one more question: where can I find a schematic for this option or can you attach/send me one?

TIA
Lourens
  Reply With Quote
Old 15th February 2004, 09:53 PM   #8
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
Quote:
Originally posted by martijn
I doubt that messing with the clock will give any improvement.

Enjoy the music!
Martijn
Contradictive.
__________________
It's only audio. Official member of the Norske Brillegeit Gang.
  Reply With Quote
Old 15th February 2004, 11:52 PM   #9
diyAudio Member
 
Join Date: Oct 2001
Location: .
When I said that you had answered your own question,I meant that the parameters you had laid down pretty much defined your only option.
The basics of a pll based sync system are outlined in the diagram below and there a number of designs available on the net.
There is the service manual for the Pass Labs D1 and the Stax Talent BD1. Both of these designs have VCXO/PLL setups though not an external reference. They are pretty much the same thing as a setup with an external reference the only difference being the internal reference. The most useful design in this case, though, is probably the Guido Tent design,
http://httpd.chello.nl/%7em.heijlige...tml/dactop.htm
and this section in particular,
http://httpd.chello.nl/%7em.heijlige...l/PLL/PLL1.htm
There is another design I have but it is somewhat over the top for your application.

ray.
Attached Images
File Type: gif vcxo-pll.gif (4.4 KB, 406 views)
  Reply With Quote
Old 16th February 2004, 07:35 PM   #10
Lourens is offline Lourens  Europe
diyAudio Member
 
Join Date: Dec 2003
Location: Utrecht NL
Default life long learning

Thanks, Ray.
I can't say I fully understand all practical implications, but I am going to chew on it (as we say in Dutch), and, with a little help from (DIY-)friends, digest it.
Just out of curiosity and for learning sake: why do you reject Peufeus straight forward clock injection, or LC's Sync Link option, in my case?

regards
Lourens
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tri Vista 21 word clock racerxnet Digital Line Level 2 18th May 2009 12:20 PM
CS8416 in sw slave mode with external clock milandks Digital Line Level 0 29th March 2009 09:45 PM
USB to SPDIF with Word Clock input??? mr-mac Digital Source 19 12th July 2008 04:32 PM
CDPro 2 with word clock in ackcheng Digital Source 1 12th November 2005 04:07 PM
CS8412, PMD100, PCM63, onboard clock + [word] clock output implementation stolbovoy Digital Source 7 3rd December 2004 07:18 PM


New To Site? Need Help?

All times are GMT. The time now is 12:58 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2