Get digital signal from an old CD-Rom without digital output - 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 31st December 2003, 12:11 PM   #1
diyAudio Member
 
Join Date: Jul 2002
Location: Boston, MA
Default Get digital signal from an old CD-Rom without digital output

I am using two old external SCSI CD-ROMs manufactured back to around 1993-1994. Both have no digital output of audio signal. I have been very happy with them as CD signal source for them give good music while playing at 1X speed and after the power supplies been modefied.

One is a NEC 3Xplus CDR-600 with decoder "SONY CXD2549Q".
Another is a Plextor 12X with decoder "SONY CXD1808AQ".

I guess there might be some way to pull the digital audio signal out. Does anyone have similar experience??

BTW, does anyone have the spec sheet of SONY CXD2549Q??

Thanks and Happy New Year!!
  Reply With Quote
Old 2nd January 2004, 12:17 AM   #2
cm is offline cm  Singapore
diyAudio Member
 
Join Date: Sep 2003
Location: Singapore
If you have a scope, probe around for the three key signals:

1. BCK - this should be around 2.1 Mhz.
2. LRCLK - this should be 44.1kHz.
3. Data - look for signal that are random, active when there is music, and dies down when there are none.

This three signals are the EIAJ or Sony format. You need glue logic to convert to Philips I2S outputs. Else you can use TDA1543A.

To help you narrow down the search, look for the DAC which should be ( I think PCM1715 ), and you will be able to know where the three pins are.

If you want SPDIF, then I cannot help you and you will need the datasheet I guess.

I used the above to find the pins for my CXD1135 and it worked great.
  Reply With Quote
Old 16th January 2004, 12:58 PM   #3
diyAudio Member
 
Join Date: Jan 2004
Location: ...
i also have a cdrom with SONY CXD1808AQ ic, but the spec. BCLK and LRCK are input, so how can i connect the signal to external dac?

Here is the spec. for CXD1808AQ :
http://www.sony.co.jp/~semicon/engli...1/a6801825.pdf
  Reply With Quote
Old 2nd February 2004, 04:07 AM   #4
cm is offline cm  Singapore
diyAudio Member
 
Join Date: Sep 2003
Location: Singapore
I think there should be another controller chip in there. From what I have read elsewhere it should be a CXD2510. You can tap the EIAJ signals from there.
  Reply With Quote
Old 2nd February 2004, 12:35 PM   #5
diyAudio Member
 
Join Date: Jan 2004
Location: ...
Does EIAJ format equal to Left justifly format
  Reply With Quote
Old 3rd February 2004, 11:54 PM   #6
cm is offline cm  Singapore
diyAudio Member
 
Join Date: Sep 2003
Location: Singapore
Don't know the technical terms. Download the SAA7345 datasheet from the philips semicon website. In there you wil find the detailed timing diagram of EIAJ side by side with I2S. I used the timing diagram information to design my EIAJ to I2S converter. It works. The schematic had been posted in this forum unders haring my digital work.

CM
  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
Opening an Ipod to get the I2S signal for a digital output gaetan8888 Digital Line Level 18 20th July 2010 08:47 PM
take digital signal from cd player tralala Digital Line Level 9 26th March 2009 06:31 AM
digital crossover w/digital output? ezkcdude Multi-Way 30 3rd August 2006 01:01 AM
splitting a digital signal bser Digital Source 4 26th October 2005 05:43 PM


New To Site? Need Help?

All times are GMT. The time now is 08:00 AM.


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