[non-entity]

Hi everybody!
 
I just had a rather foolish idea that put a grin on my face, so I thought I should ask if this could work. Caution: I just realized how hard it is to put this into words, so what I am going to write might sound ridiculous. Well, I am using my old DVD-player made by Panasonic as source, more precisely the model DVD S-295 (which doesn't support DVD-A). It sounds sweet to me, but changing discs is getting annoying, so I was wondering if one could stream audio from a PC to it. I was thinking about 'emulating' DVD-playback to feed bite-sized audio to the device (e.g. a 96 kHz/24 bps DVD-V LPCM stream).
 
The main idea was to just use parts from an external drive enclosure with USB connector, but after seeing the three connectors which connect the drive with the player, I was quite baffled. Are these connectors standard connectors, or are these proprietary? I uploaded three pictures for you in the hope that one of you guys knows what kind of connectors these are ...
 
Picture 1
Picture 2
Picture 3
 
My dream is to create a foobar2000 component which wraps the source file into a DVD stream (is this possible or even necessary?) that is eventually transported to the player to feed any desired headphone amp in the end. (My CMoy, for instance. Haha, life kinda sucks when you're a student and can't afford 'proper' equipment!

) Well, this would probably require more work than this, right? Would the firmware just accept 'foreign' input? Probably not ...
 
Has this been done before? Could this actually work? And would it be worth the effort? (By the way: a PCM1780 DAC is in there and I really enjoy the audio output.)
 
Regards,
r

 

[Pageygeeza]

I know roughly what you're getting at.  
 
By the looks of it, it's just a standard DVD transport, meaning it is only that hardware to read a disc and nothing else.  The three should be:
 
1:  Power for drive spindle and tray motor
2:  Power to move the OPU from the center to the outside of the disc
3:  Main connector for the OPU itself to read the information from the DVD
 
The board/boards these connect to deal with moving the head across the read surface/lens focusing/spindle speed and probably a few other things I'm forgetting.
 
I suppose you could theoretically stream raw binary audio through the connector to the AD converter, but you'd then need to make another interface to revert the information from usb back to raw binary to go through the player.
 
Pic 2 is the cable where the binary information is sent.
 
Hmmm, you got me thinking now.  :S

 

[non-entity]

 
Quote:

1:  Power for drive spindle and tray motor
2:  Power to move the OPU from the center to the outside of the disc
3:  Main connector for the OPU itself to read the information from the DVD

Thank you, this is useful information! Before looking into the player I hoped that I'd find usual computer-related connectors, but well... I have never done anything remotely similar to this, so I'm completely stumped. :-/

But hey, if there's a doable way to connect a PC with any DVD-player, almost every tinkerer would have the parts for a DAC in the living room, right?
 
Quote:

but you'd then need to make another interface to revert the information from usb back to raw binary to go through the player

 
Would an interface like this work similar to a IDE/SATA host adapter? Or at least what is in a external drive enclosure? It is basically the same thing, only with a different transport method, right? Now it would be quite handy to know how these connectors are named.
 
Thank you so far for the input, I really appreciate this!

 

[Pageygeeza]

 
You'd need to find the correct data path to the DAC.  I'm not sure how the OPU sends data, so I'd suggest you read up on CD technology first before you delve too much into this project.
 
 

 

[non-entity]

Thanks again for the information! Lately I had a lot to do which means I didn't do anything, but I think it's not worth the effort. It was a little amusing thought, nothing more.
 
Still, the little tinkerer inside of me thinks that something like this could be the equivalent of the CMoy in the DAC-department.

 

[Pageygeeza]

On thinking about it, I have an old CD-ROM drive that can be stripped down, might have a look at that later.  It has audio out straight from the board, could be fun!

 

[non-entity]

This would also be great for discs with "Copy Control", I assume. Well, only in case somebody buys or bought such discs. What kind of audio out do you mean? I have an old drive with a female headphone jack (plus volume control), but I guess you are talking about something else.
 
Did you already check it out?

 

[ROBSCIX]

Find the DAC on the board and get the specfication sheet for that model, that is a goodplace to start.

 

[Pageygeeza]

Thanks for reminding me guys.
 
Right, couple of things I've found:
 
The main VLSI chip does quite a bit.  Error correction, reading / interpreting disc info to determine speed, lens placement and so forth.
As well as that it's dealing with data connection to the IDE connector.  Sending / receiving data to / from buffer.  Digital data out, so this thing without modification can output raw audio binary data!  
 
Analogue audio out comes from the VLSI too, but there is another IC which I have no idea what it is.

 

[Pageygeeza]

Quote:

This would also be great for discs with "Copy Control", I assume. Well, only in case somebody buys or bought such discs. What kind of audio out do you mean? I have an old drive with a female headphone jack (plus volume control), but I guess you are talking about something else.
 
Did you already check it out?

The audio out I'm looking at is at the rear of the CD ROM.  Only the more older drives will you find them.  The two drives I have are from 2003-2004.

 

[non-entity]

 
Quote:

The audio out I'm looking at is at the rear of the CD ROM.  Only the more older drives will you find them.  The two drives I have are from 2003-2004.

2003 to 2004? That's great, because I have such a drive lying around somewhere, I just have to find it! I'll check if it's a drive with audio out.

 

[Pageygeeza]

There was also something else I noticed.
 
The headphone out jack has a class AB preamp.  

 

[non-entity]

 
Quote:

There was also something else I noticed.
 
The headphone out jack has a class AB preamp.  

Which drive is this? As you likely can tell by now I don't know a lot about CD drives, but this sounds pretty unusual to me. I always assumed that most drives are built rather simple and cost-effective, so to me it sounds like you've got a good drive there.

 

[Pageygeeza]

All, if not most of early optical drives have headphone outs on them.
 
The two drives I've been messing with are:
 
Lite-on  SOHR-5238S
SONY CRX225A
 
Considering how the drives are running off one main IC for mostly everything it's hard to fathom where all audio is really coming from.  There are 3 main audio outs, but can't figure if they're all coming from the same point.  I can't find the info on the main IC so it's hard to work out.  I don't know where the dac is situated, it could be on the main IC or could be on another one.  :S
 
I'll do a full strip down and take pics tomorrow, might help actually.  

 

[non-entity]

 
Quote:

 
I'll do a full strip down and take pics tomorrow, might help actually.  

This is good news, nice! I just tried to take apart this external iomega drive I have lying around here, but apparently it is glued together. There is probably just a certain spot where I have to pry with a screwdriver or something, but right now I'm a little in a hurry and I don't feel like breaking something since it isn't mine. It even has two RCA plugs on the back and I just plugged my headphone amp in to see if there is noise. Well, there is. It actually sounds really nasty when I turn the volume up, but I didn't try it with music. The amp itself doesn't introduce any noise to the signal, so it can only be the drive / the drive's amp stage / DAC or whatever. (kinda funny to me since there was no load... almost like very old gear from the seventies)
 
I guess using the analogue plugs of such an older drive is rather counterproductive, but using a digital out seems promising to me. What I really would like is to figure out how to transport audio from USB to my DVD player's internal drive connectors. I guess wrapping WAV files during playback into a DVD stream using software can't be so much of a problem, but the problem I see here is to just get or make the right connector. I can't get my head around it honestly.
 
What have you in mind? Are your plans to use one of these drives as DAC/transport, or is there something else you want to do? I guess one can learn a lot by simply taking such a drive apart, especially if there's already basic knowledge. It would be really awesome if there was sort of a basic way to turn possible candidates for DAC usage actually into a DAC. There are a lot of gadgets in virtually every household that would do the job, and I'm sure that using a PC as source would seem attractive to many people, but if there's no practical way than of course it is nothing but an idea...

 
Whoa, sorry, now I wrote a little much. Cheers!