I own an 80's cd player, the DENON DCD-910A. It uses the PCM56P as a DAC and it still sounds very good.
I was thinking to use it as a DAC, but I have to find out a way to install a SPDIF input somewhere into the existing circuit.
Since the most of my audio files is stored in my computer, I want to use it as a DAC and isolate the CD.
Is there any way to put a SPDIF input (or USB or HDMI)?
I have attached the circuit and IC pages from the service manual.
I was thinking to use it as a DAC, but I have to find out a way to install a SPDIF input somewhere into the existing circuit.
Since the most of my audio files is stored in my computer, I want to use it as a DAC and isolate the CD.
Is there any way to put a SPDIF input (or USB or HDMI)?
I have attached the circuit and IC pages from the service manual.
That is not too difficult to do, with or without digital filter?
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The question is how much of the character of the cd player do you wish to retain ? If you wish to remain as close as possible then you go in at the digital filter. If not, you can bypass the filter and drive the dacs directly.
However either option comes with problems that need to be overcome but I am sure Lampie519 will have them solved in no time.
However either option comes with problems that need to be overcome but I am sure Lampie519 will have them solved in no time.
The thing is that the original digital filter will accept i2s. In case you want to use the filter it is easy as you just buy a SPdif input card with i2s output and build a small switch (74hc157) to switch between the CD player i2s and the second source.
As the datasheet is not available i can not determine if the filter will be able to handle the i2s signal or not. In any case it will be possible, just how much effort would you like to put into this adventure?
As the datasheet is not available i can not determine if the filter will be able to handle the i2s signal or not. In any case it will be possible, just how much effort would you like to put into this adventure?
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Here the circuit for the switch (needs to be modified a bit for 2x i2s inputs).
The input board could be purchased off the shelf and modified.
CS8416 S/PDIF decoder
I found the switch as well...
Kit Two-way Audio I2S two I2S in/out one out Switching Module - Audiophonics
The input board could be purchased off the shelf and modified.
CS8416 S/PDIF decoder
I found the switch as well...
Kit Two-way Audio I2S two I2S in/out one out Switching Module - Audiophonics
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There is no harm in seeking "expert" advice. But don't take it - Rudolf Kompfner
I wouldn't suggest an approach if I hadn't built it and knew it worked.
I wouldn't suggest an approach if I hadn't built it and knew it worked.
Modifying an existing old player is maybe not the best thing to do.
Building a seperate DAC would be the best option and then you can decide what chipset to be used.
Best regards, Frank
Building a seperate DAC would be the best option and then you can decide what chipset to be used.
Best regards, Frank
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@rfbrw
It is a matter of glue logic and it will work in any case. No rocket sience involved here.
Best regards, Frank
It is a matter of glue logic and it will work in any case. No rocket sience involved here.
Best regards, Frank
I like the sound of this CD player DAC. I will call it a kind of audiophile. It's very natural and flat. So I would like to give it a try.
As I understood, the I2s input would be the best option, isn't it?
Will I need a receiver board (e.g. from HDMI, coax or optical to I2s) to do this?
I also found the pin layout of the SM5817 from a service manual of ONKYO DX-C300. It uses the same filter and DAC IC as the DENON.
So, is it simple to add this input?
Please, keep in mind that I don't have to much expierience in digital audio as I have in analog.
As I understood, the I2s input would be the best option, isn't it?
Will I need a receiver board (e.g. from HDMI, coax or optical to I2s) to do this?
I also found the pin layout of the SM5817 from a service manual of ONKYO DX-C300. It uses the same filter and DAC IC as the DENON.
So, is it simple to add this input?
Please, keep in mind that I don't have to much expierience in digital audio as I have in analog.
It looks like these chips are interchangable, However, this is not a beginners project, Only if you like to experiment and do not mind to fail it is a ok to proceed. If you do care about your player then buy a second one to play with or just build a seperate DAC. Then you learn more and no need to alter a fine working machine.
Board that have a SPdif receiver can be found anywhere and are cheap. You will need to find the i2s signals and pass these through the switch (as explained earlier). This is not a difficult job if you are experienced but almost impossible if not.
Best regards, Frank
Board that have a SPdif receiver can be found anywhere and are cheap. You will need to find the i2s signals and pass these through the switch (as explained earlier). This is not a difficult job if you are experienced but almost impossible if not.
Best regards, Frank
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True no need for rocket science but it does require a level of understanding that acknowledges that there is more digital audio than I2S, which is just one format and a format not be found in the DCD910A.
Indeed, not all is i2s. In this case it looks like only 1 signal needs to be reversed to make it so.
I was just answering to the inquiry if this can be done. The answer is : Yes it can...
Sure, it is a level of understanding needed to successfully finish this project.
I also like to encourage people to try new things (as we all did) and to say right from the start it is difficult or impossible doesn't help.
Don't you agree?
I was just answering to the inquiry if this can be done. The answer is : Yes it can...
Sure, it is a level of understanding needed to successfully finish this project.
I also like to encourage people to try new things (as we all did) and to say right from the start it is difficult or impossible doesn't help.
Don't you agree?
While it not exactly easy, it isn't monumentally difficult either. It is about knowing how to get from where you are to where you want to be and Mr Lampie519's comments merely serve to obscure the path. The I2S serial audio interface is a Philips protocol. The DCD910A has Sony DSP preceding the digital filter and it has a Sony serial audio interface, very different protocol indeed. You also have to consider how you are going to place your input board, be it HDMI, USB or SPDIF, into the same clock domain as the DCD910A. I would suggest it is a task that requires careful thought.
No. It is one thing to say it can be done. Quite another to suggest one needs a drill when the correct tool is a screwdriver.
Maybe going to i2s is not usefull in this project. In my first entry i showed a circuit that will work without glue logic (SPdif input only, 2’complement).
Best regards, Frank
Best regards, Frank
For more info about the differences can be found in this thread:
I2S transcoder - diyAudio
And this:
Difference between true i2S and converted EIAJ
I2S transcoder - diyAudio
And this:
Difference between true i2S and converted EIAJ
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Thank you both for the very interesting info.
Of course some things are still obscure to me.
A few more questions:
1. If I'll go for the SPDIF (coax) input do I have to use a receiver or I'll connect the input wire straight to SM5817? Which pins should I use?
2.What kind of signal comes out of the CD transporter and connected to the board input? Is it possible to use this board input? (of course CD player will be out of use).
Of course some things are still obscure to me.
A few more questions:
1. If I'll go for the SPDIF (coax) input do I have to use a receiver or I'll connect the input wire straight to SM5817? Which pins should I use?
2.What kind of signal comes out of the CD transporter and connected to the board input? Is it possible to use this board input? (of course CD player will be out of use).
If you use an input receiver then first you go to the switch (74HC157) otherwise you can not switch between the sources.
If you do not want to switch but only use the player as DAC then you can omit the Multiplexer (switch).
In the first diagram you can see a CS8412 receiver chip. It is a bit outdated but easy to work with. Newer chips are available (CS8414 or CS8416) some are SMD components and are difficult to work with as DIY'er. I would try to get my hands on some finished boards available on the web as it saves a lot of work and they are not expensive.
Pin 5,6 and 7 are your inputs of the digital filter (do not forget ground)
What kind of equipment do you have to check any signals? You will need to be able to confirm that all signals are correct.
You should measure at resistors R251, R252 and R254. These resistors can be removed instead of cutting the copper if you proceed to modify the player.
I hope you think again before doing so.
Best regards, Frank
If you do not want to switch but only use the player as DAC then you can omit the Multiplexer (switch).
In the first diagram you can see a CS8412 receiver chip. It is a bit outdated but easy to work with. Newer chips are available (CS8414 or CS8416) some are SMD components and are difficult to work with as DIY'er. I would try to get my hands on some finished boards available on the web as it saves a lot of work and they are not expensive.
Pin 5,6 and 7 are your inputs of the digital filter (do not forget ground)
What kind of equipment do you have to check any signals? You will need to be able to confirm that all signals are correct.
You should measure at resistors R251, R252 and R254. These resistors can be removed instead of cutting the copper if you proceed to modify the player.
I hope you think again before doing so.
Best regards, Frank
