Philips CD950 schematics needed

Status
Not open for further replies.
Jump to Latest
#61
I do not now. I bought it on Allegro.pl (polish auction similar to ebay). After power on it play clearity sound by few minutes only and next go to harsh sound. So I disassembled its. I think that CD820 sound deeper (maybe dynamicaly) then CD950, but I can make a mistake - few minutes is too short to develop myself opinion. But idea of modification of CD820 is very practise because working on CD820 I parrarelly use CD950, and next sell it. Clean profit. In opposite, I will be working on CD950 and CD820 will be throw out to cellar.

Both CD Players were built on different maechanisms: CD950 on CDM9/44 and CD820 on CDM4/19 (composite frame but look better than made of sheet metal CDM9/44), but I suppose both mechanisms based on similar appication (TDA8808/8809). CD950has better looking display than green old display of CD820 but maybe it would be possible to confues display (I do not know because I have not either schematic or Service Manual of CD820).

Mt generally idea is to modyficate any CD player to get good transport with I2S output (maybe in future I will try to build good DAC) and with S/PDIF output to connet it to AudioAlchemy DAC+DTI+. So I get two way of connect CD in my system.

In DIYAudio I found opinion that CD with Bitstream conversion never sound dynamically?! And that CD950 has bad designed PCB (ground loops, both TDA8808 and TDA 8809 have badly ground connection, weak main ground point, bad composite of PCB, etc.). Mayby you have any experiences or opposite opinions in this matter.

JKoch
 
#65
JKoch said:
QSerraTico_Tico

I just send it to you third time. Up till now I did not received any return message from System Administrator.

JKoch
Click to expand...
Hi I appreciate your kindness but the file is simply to big for Yahoo email as the max is 10MB.
Apparently ur mail is "eaten" in the process.
:dead:

Uploading to rapidshare.com and sending the link by email seems to be the only way. And it's free of charge!
 
#69
hjsplit is, I assume, a program that will take a large file, split it into several smaller files of data, which can then be sent in pieces, and then put back together at the other end.

Jkoch,
I think I would decide on which player actually works. Is it the 820 that fails after a few minutes?
Its a tricky decision, because you have a CDM9 feeding a bitstream DAC, versus a CDM4 feeding a 4x oversampled 1541. One, IMO opinion has a better transport, whereas the other IMO has a better digital filter and DAC.

Replacement CDM4s are easier to find too.

Anyway, if you do want to do your own DAC, I'd stick with the CDM9 as its a better transport. And you'd have a TDA1541A you can use for your first DAC. Bargain.

I agree, there have been several comments on the CD930/931/940 about ground loops and decoupling issues. The CD950 is a different PCB, with less SMD components. It might not be the same issue.
Because I've disconnected half the circuitry on my 940, I hope th chances of ground loops are reduced, I do intend to investigate and sort one day, I've paid little attention to grounding and regulation etc, purely because I've removed essentially half of the circuitry, so the job of regulation is a lot easier.

I believe that either the 8088, or the 8089 does indeed have a decoupling cap missing. Shocking as it is, but its fairly easy to solder one on to the legs of the chip. I gather some decoupling caps are a long way away from their associative ICs, but again, it should be fairly straightforward to add extra caps. That's typical CDP modding.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=99920&perpage=10&highlight=&pagenumber=1
 
#72
Hi Mahrdad

I sent to correct address. The message from System Administrator was:
"Md.samimi@Gmail.com on Tue, 12 Jun 2007 20:45:19 +0200

The content length of the message is too long for the recipient to
take delivery"

The file has too big size. I try to send it by hjsplit software mentioned by Guido.

Regards

JKoch
 
#75
Hi Phil

Thanks for the explanatio of abr. hjsplit. I use it and expect results.

I think you have a right to began modifying of CD950. Especially that I do not know what is damaged in CD820 and how much that repair will be cost. And in future I maybe decide to built external DAC based on the TDA1541A (as yours). Till this moment I will be use AudioAlchemy DAC (now I change all old electrolytic caps near all internal PSU regulators - I was built Power Conditioner including trafos+bridges+elcaps for each AA components separately to avoid original strange black box PSU of AA).
By the way: what quality of sound from the DAC you got? Are you satisfied of reached results?

I just started read your post about CD940. When I end of the very interesting description, I suppose I will be have few question about your modification.

Regards

JKoch
 
#76
My first TDA1541A DAC was very badly made (you can see in that thread!), but it surprisingly sounds good.
Its a NOS DAC, so its a fairly low frequency circuit, which is easier to implement, and should be less sensitive to jitter.

It is easily comparable to the modded CD63 I had, maybe better.
I really am pleased with it.
At the moment, I am finishing of a dedicated power supply, and then a sensible enclosure, then I shall begin my DAC 'MKII'. Basically, it will be multiple DACs (I'll start off with 2, then go to 4, and if I notice any improvement, I might one day try 8), with balanced (XLR) outputs. I also have a SAA7020 and I want to try 4x Oversampling - probably with only one or two DACs (so far, I haven't had much luck with it yet, but its early days in my experimenting).

Anyway, this is off topic a lot now. Basically, it sounds great, but the most important step I made was getting the 940 and giving it a diff I2S output.
 
#77
JKoch said:
Thanks to it you could get the big file in two parties.
Click to expand...


Hi JKoch;
Thanks.But I Didn`t Recieve The Mail.
bawling.gif
 
Status
Not open for further replies.
Top Bottom