DIY CD drive based on a computer CDROM

[Sergelisses]

I was able to find and tap into the 3 I2S signals from the controller chip of my CDROM and feeding it to a TwistedPearAudio DAC. Is this the best jitter performance I can get? What else can I do?


Tell me more ....
Where did you found the I2S signals ?

Serge

 

[glt]

Found an old CDROM (built in 2000). Took it apart and found the datasheet of the controller chip (a Windbond chip). Noticed that there are 3 audio out signals: LRCK, BCK and Data (These are not named I2S but are the same as the I2S signals). I have a Twistedpearaudio reclocker so I feed these 3 signals to the reclocker. Nothing. Then I change the settings to the reclocker to 16 bit input and right justified. I get music.

I tapped the 3 digital signals by soldering wires (cat5 wires) on vias. Then I rerouted them to the 4-wire analog plug in the back of the CDROM (first removing the analog connections to the board) and used the analog CDROM cable you find inside computers. This cable seems perfect since it has 3 signal wires and a ground shield.

The reclocker does not take the clock signal from the CDROM (In fact I did not look to see where it can be tapped. There is a 33.8688 clock but I'm not sure if this is the clock that can be fed to a DAC). The reclocker generates its own clock during the resampling and sends 24/194KHz to the DAC

 

[Sergelisses]

Today it's not easy to find the datasheet of the controller chip .


I think your solution to use directly the I2S signals is the best .



Serge

 

[glt]

In my experience, datasheets are easy to find. Search for the part number or Manufacturer plus part number.

 

[afhifi]

I have referred the feeder of the CDrom inserting to the 5V a couple of condensers from 22000uF, the controller now works well with many drives of various brands.
I don't know why without the condensers the 5V has a very strong trouble when the CDrom departs.

AFHIFI

 

[minivan]

Found an old CDROM (built in 2000). Took it apart and found the datasheet of the controller chip (a Windbond chip). Noticed that there are 3 audio out signals: LRCK, BCK and Data (These are not named I2S but are the same as the I2S signals). I have a Twistedpearaudio reclocker so I feed these 3 signals to the reclocker. Nothing. Then I change the settings to the reclocker to 16 bit input and right justified. I get music.

I tapped the 3 digital signals by soldering wires (cat5 wires) on vias. Then I rerouted them to the 4-wire analog plug in the back of the CDROM (first removing the analog connections to the board) and used the analog CDROM cable you find inside computers. This cable seems perfect since it has 3 signal wires and a ground shield.

The reclocker does not take the clock signal from the CDROM (In fact I did not look to see where it can be tapped. There is a 33.8688 clock but I'm not sure if this is the clock that can be fed to a DAC). The reclocker generates its own clock during the resampling and sends 24/194KHz to the DAC

i have a 1999 sony cdrom, also has an windbond chip in there, part number is w29ee512p, goolge it up, it's a cmos flask memory chip, so how do u find out the i2s signal from it? ( the digital signal seem to come out from that chip ,but i have not use a multimeter to confirm yet)

 

[glt]

You have to identify the controller chip (in my case, the windbond chip is the cdrom controller chip), then the pin out will have signals with names similar to the ones from I2S. Some chips will not output I2S type, but directly SPDIF, so it depends on the controller chip. Its got to be one of the bigger asics in the board

 

[dearangelo]

Konnichiwa,



Well, if use async read and the ATA interface it should be fine, simply define an adjustable float relationship between master clock and output clock on S/P DIF.

HOWEVER, most decent external DAC's do not like "varispeed" too well, so it makes most sense with an I2S interface.

BTW, having a few % pitch is a good idea, as pitching music slightly flat of 440Hz can give a more "relaxing" perception and pitching it sharp will make it seem more "energetic" (no kidding - it is important to hit the right frequency too).

Sayonara

!! I have been reading thru, looking for a cd drive to player diy project to do...
excellent Idea the pitch thing...
so will you help me and save me the reading, direct me to the place where the fun starts, where the drive gets picked and dissected?
thank you

 

[gabrielbecheanu]

Hi
I have seen on EBay a cd-rom controller, it is interesting to make a cd transport but my big question is how accurate is the cd audio reading. We all know that when ripping a cd using EAC for best result is to configure the cd rom drive offset for best accuracy.
How we can make a cd rom using an external controller to read the audio cd format very well.
If this is possible I would like to make a cd transport for my CS4398 DAC
This is the controller iv seen on EBay.
CDROM controller DIY kits with BlueWhite LCD Display SE - eBay (item 260527580989 end time Mar-23-10 02:02:37 PDT)
Thanks

 

[dearangelo]

correct me if I am wrong, but accurate ripping has a value if you are reproducing the cd, and it is compared against the dbases, why would it be of any difference if it is a relative offset and not a referenced offset?
anyways, I ordered the same gadget for my plextor, I will live with it, it looks interesting to do a nice moding.
next step would be to get the cdpro2lf whatever, the works...
that should be a total...
regards
Angelo

ps perhaps this might be o a little help
http://forum.dbpoweramp.com/showthread.php?t=20731

 

[gabrielbecheanu]

Hi Angelo
I have a cd-rom with a play button on front and digital output.
Next week I will make a test between a modified Onkyo DX 6850 and the cd-rom via a Crystal 4398 base DAC. I am so curios how big is the difference if is any. If the result will satisfy me I will order one as well.
My concern was to have an accurate reading at low speed, best at 1X.
After you receive the controller please inform me about the cd rom speed noise.
Best regards

 

[wishmasterX]

Hi,
do you have any idea - schematics of power supply for CD-ROM?

 

[EBM_dude]

Any 0-12V AC transformer that can supply enough current with smoothing voltage regulation to +5V and +12V will do the job. Watch out for the current draw of the drive, though. Mine wants a hefty 1.5 amps on the +12V line and 1 amp on the +5V line. It's probably time to break out those trusty 2N3055 and some Z diodes again.

 

[MCLL]

Use this transformer to build power source for CD-Rom drive

 

[icsnerdics]

You have to identify the controller chip (in my case, the windbond chip is the cdrom controller chip), then the pin out will have signals with names similar to the ones from I2S. Some chips will not output I2S type, but directly SPDIF, so it depends on the controller chip. Its got to be one of the bigger asics in the board

i've found a Creative CDROM that seems to be a Samsung SCR2430 CDROM, reading the CDROM controller IC and the ADC/DAC IC datasheets, i've found i2s pins on both of them.
they are called LC895196 and TC9444(A)F.

Creative Cd-rom I2C.zip datasheets can be downloaded here.

The LC895196 is a large scale integrated circuit equipped
with CD-ROM functions and an internal ATA-PI (IDE)
interface.

The TC9444F is a karaoke chip for such applications as
equipment for CD/LD players, mini component stereo sets,
radio-cassette players, and VTRs.
With its internal AD/DA converter system, the TC9444F can
offer such karaoke functions as echo, vocal canceling, and key
control on a single chip in addition to such digital signal
processing (DSP) features as sound field control and bass/treble
control.
Because the program and coefficients are stored on internal
ROM, the IC can be controlled by simple settings.

6. The D/A Converter Interface
DLRCK, DBCK (output)
These are the DAC pins made by XTALCK0 or XTALCK1.
DSDATA (output)
This outputs serial data to the DAC.

this is from the LC895196 datasheet.
but no info about i2s and specs.

40 SDO O Digital audio data output
41 BCKO O Bit clock output
42 LRCKO O Channel clock output

and this from the ADC/DAC.

SYNM2 SYNM1 IBIT2 IBIT1 Format BCKI
0 0 1 1 IIS-compatible 24 bits 64fs

soooooo seems that the DAC can handle a "output i2s" signal and also a "input i2s" signal from the cdrom controller (i hope).

seems that SYNM2 & SYNM1 from the bootstrap are 0, but i don't know anything about the initial value of IBIT1/2, they have to be 1.

so here comes the questions...
it's supposed to be better to get everything from the controller?
and if "yes", where the clock cames from? an interface from the CDROM controller or ADC/DAC?

someone can give me a clue?
thanks a lot.

 

[TBKK]

I have try to connect the digital output of my DVD rom to my CAL dac
and it does not work. I have also try the TTL to Coax converter

but still no succes.

I have an normal cd player with digital output and it works with the DAC
do you please have any suggestion

Thanks
TBKK

 

[zakman35]

This is my version of a CD player based on a computer CDrom.

I used a "Compaq CDROM LTN-486S 48x" ide device that had the best sound out of allother cdroms had in stock.

Sound quality from the digital output, is Very Good, detailed and natural, (analog output sucks).

I am using this as my main CD player together with my DAC.

YouTube - DIY CD drive based on a computer CDROM

 

[TBKK]

I have bought an old Rockna board working perfect
need to change the LCD for an PLED of VFD have anyone has experience with this
change

 

[tiefbassuebertr]

in this case this thread could be of interest:
Silicon Chip CD Controller

 

[TBKK]

I got an problem;

i hear an digital sound looks like static sound when connected the
digital output to an DAC i have convert the SPdif TTL to COAX
does anyone knows this problem