mods for old CD-player
I am looking into modding/upgrading my old SONY cd player: CDP-M18 is the model.
It uses KSS240A transport and some other SONY chips for DAC and output stage (as i presume), also a linear power supply (which is a good thing)
I want to make my own DAC and output stage for the player, but the CDP doesnt have a digital out, so i have to find the SPDIF or I2S outs inside the player's circuitry.
Anyone who knows how i can find them, please lemme know.
Also I appreciate any info on how to do other mods (for starters) for the unit, or related information. (can't really find no info about the particular model or even the transport on the web)
I found the i2s lines in my player, just by going on google and looking at the datasheets for the ICs inside the player, and found the datasheet for the DAC, then soldered wires onto them, and into my dac. It also helps to have an oscilloscope to verify that you have i2s data coming over the lines, a clock line, data line, and a left/right line.
pardon my ignorance, but whats IC?
Also, i noticed that the CD while inside the transport and spinning, is kinda wobbling - with an amplitude of about 0.5-1mm both vertically and horizontally - its not the CD problem since i tried multiple CDs with the same result.
The metal circle on the top of the transport (dont know what its called) that also spins, also seem to wobble (only horizontally though, with amplitude of about 1mm)
Is there a cure for that? (like putting a weight on top of the metal circle) I dont want my CDP to develop skipping and all, what are other things i can do to it to reduce jitter
Re: mods for old CD-player
You need to find out which digital signal processor is used.
Very probably you have to pull a pin high to enable digital out.
Please note what you call I2S signals are not Philips I2S but probably Sony/Burr-Brown format. Meaning you can directly drive a AD1865 but not a TDA1543.
As for the wobbling, it seems like a bad clamping system.
Thanks a lot for the replies!
"Meaning you can directly drive a AD1865 but not a TDA1543"
I was myself surprised to see TDA1543A DAC inside of this thing :nod: (thats a good dac, right?)
Here are the chips inside, pls comment on the ones you know about - i tried to find datasheets on them without a result (except for the dac)
SONY d75308 545 (i think it controld the LCD)
SONY CXD2554M (there is a crystal hooked up to this one)
5285 (and has a mitsubishi logo before that number)
LA5601 (10 pin chip)
Here are the mods i considered thus far, pls give your comments and directions:
- put a round weight on the metal circle on the transport.
- improve the clamping system (how do i do this? stronger magnet?)
- dampen the crystal (whats the best material for this, i got some liquide silicon - is it good for the application? Also do i have to lift it above the PCB?)
- As i mentioned there is a linear PS which feeds the circuit only +7V. I was thinking of batteries for the whole thing, or PS for transport and batteries for analog stage, and better yet separate battery for the clock - pls give oppinions on that one.
- If PS way - shottky+BG on PS
- another great thing about the CDP is that its got a SH^%$T load of free space inside the case, which makes it great for extra circuitry or batteries inside, oh and did i mentioned i got the unit on ebay for $12 including shipping and its in wonderful cosmetic condition.
Thanks a bunch
Digital Out on Sony Player
The digital out is pin 60 on the CXD2500Q.
You have to pull pin 59 high to enable digital out. Just connect pin 59 to +5V. This may be tricky as it is probably soldered to ground.
Also note the difference between the TDA1543 and the TDA1543A:
For starters, my advice is to leave the dac alone and devote your time to the analog output stage and power supply section.
I have found that the analog output stage and its power supply
have a BIG impact on the sound :nod:
For example, I own a Pioneer DV-45A universal player. I recently replaced the +12V supply to the output stage from a switch mode supply to a linear supply and this made the sound MUCH more enjoyable to listen to. My external dac (the dAck!) uses sealed lead-acid batteries for the dac chip and analog output stage, and this is even better! :cool:
www.lcaudio.com sells a great clock upgrade that you may want to consider, along with their zap output stages. Elso Kwak also has a clock that has a solid reputation.
Do you have schematics? I recommend you get a hold of the service manual so you can really get an understanding of what you're dealing with and where big improvements can be made. A service manual is around $30 USD on average.
There are a ton of things that you can do to really improve the sound of your player. How much are you willing to spend on mods? There a some that will make more of an improvement than others.
If you're not too experienced with a soldering iron and dealing with fine-pitched IC's, try to practice on a junk board from something else. Practice removing components without damaging the board traces and pads, and practive installing parts. By the time you start soldering your player, you want to be able to do very clean work :wiz:
Thanks a lot for replies , guys
- Can i please have your latest clock design, over to firstname.lastname@example.org. Can it be powered with batteries?
- Do you by any chance have a schematic of a CDP that also uses CXD2500Q and TDA1543A, i dont fancy bying a manual for my CDP for $30 + shipping, so i just need a sample schematic to guide me.
- What exactly pulling 59 leg translates to? Would it give me normal I2S in 2's complement? or still in binary offset?
I am not very well versed in this kind of digital circuitry, so take your time while you explain.
- I would also like to know where to get the initial analog signal from DAC to redirect it to my own output stage, in case i decide to stick with this TDA1543A, also after i do redirect it - do i have to cut the trace that previously connected it to the old (player's original) output stage? or there is no need?
- If, for instance my CDP uses 3 different voltages at different locations of the circuitry (say +7, -5, +5) is it possible to use 2 power supplies instead of getting noise from the regulators? (1 for +7V, and 1 for +/-5V), or regulators also limit the current ?
I get quite a lot of hiss while the CDP playing, i get less hiss even from my soundcard :dead:
- At first i will do what you recommend - i will leave the DAC be and work on PS and output.
- thanks for a lot of useful points
Too many questions
You can download the KWAK-CLOCK here:
The KWAK-CLOCK can be powered from batteries. The powerconsuption is very low, but I did not find any advantage doing so. Pulling High means connecting to +5V as I said. No more no less...... The output at pin 60 is not I2S but SPDIF format ready to go to the SPDIF output. (Digital out)
The TDA1543 will NOT work directly connected to the CXD2500Q as you need glue logic to convert the Sony/Burr-Brown format to Philips I2S format. See the attached picture. This is taken from the Cal Rubinson article in the Audio Amateur. Personnaly I would use 74HC04 and 74HC74. No garantee it works!
And to make matters even more complicated the TDA1543A will not work here, with or without the gluelogic in the NON-OS mode. I am not sure about the last questions....
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