replace old cd-player drive
Hello Tarasque,
It's not directly possible to replace the mechanical part of a normal cd-player with a cd-rom player. However it might be possible to use the DAC in your Denon player but you still have to add the control for the IDE based CD-ROM player.
The control in your Denon player controls directly the hardware of the laser while a CD-ROM player has all the electronics on board and has to be controlled via the IDE interface.
Hello Tarasque,
It's not directly possible to replace the mechanical part of a normal cd-player with a cd-rom player. However it might be possible to use the DAC in your Denon player but you still have to add the control for the IDE based CD-ROM player.
The control in your Denon player controls directly the hardware of the laser while a CD-ROM player has all the electronics on board and has to be controlled via the IDE interface.
All,
Has anyone actually measured the jitter on the SPDIF digital output coming out of a CD-ROM? This past weekend I bought an EPO CD-ROM for $25, and connected the digital output to my
dac (Ack!Industries dAck!) and to my surprise the sound was
not bad at all
I have a basic o'scope, and was able to tell that the digital out signal level is 0-5V (not true spdif voltage level of 0.5Vpp, I think). The dAck has no trouble with this voltage level, but I am curious about the jitter improvement aspects of this thread.
This CD-ROM uses a MediaTek 208-pin MT1199 chip, which uses an internal PLL for clocking, and sends out the digital output.
Since there isn't an external crystal for this chip, I was wondering about how much jitter improvement can be made, and is there really that much jitter in the first place?
The idea I've read on this thread of sending the digital output to a buffer and then reclocking it out with a precise clk sounds interesting to me. Has anyone tried this with positive results?
There is also the issue of making sure the output has enough current to drive the cable and dac properly without any distortion of the eye pattern.
BTW, I am using a 12V 1.2A and 5V 2.5A linear regulated AC-DC power supply modules made by Acopian.
What is the state of this project? By reading this thread, it looks like there is a lot of time and investment of ideas here, and I like reading everyones points of view. For now, I just want to focus on getting a very low jitter digital output signal to feed my dAck, and then look into the IDE controller, possibly an LCD, etc.
Has anyone actually measured the jitter on the SPDIF digital output coming out of a CD-ROM? This past weekend I bought an EPO CD-ROM for $25, and connected the digital output to my
dac (Ack!Industries dAck!) and to my surprise the sound was
not bad at all
I have a basic o'scope, and was able to tell that the digital out signal level is 0-5V (not true spdif voltage level of 0.5Vpp, I think). The dAck has no trouble with this voltage level, but I am curious about the jitter improvement aspects of this thread.
This CD-ROM uses a MediaTek 208-pin MT1199 chip, which uses an internal PLL for clocking, and sends out the digital output.
Since there isn't an external crystal for this chip, I was wondering about how much jitter improvement can be made, and is there really that much jitter in the first place?
The idea I've read on this thread of sending the digital output to a buffer and then reclocking it out with a precise clk sounds interesting to me. Has anyone tried this with positive results?
There is also the issue of making sure the output has enough current to drive the cable and dac properly without any distortion of the eye pattern.
BTW, I am using a 12V 1.2A and 5V 2.5A linear regulated AC-DC power supply modules made by Acopian.
What is the state of this project? By reading this thread, it looks like there is a lot of time and investment of ideas here, and I like reading everyones points of view. For now, I just want to focus on getting a very low jitter digital output signal to feed my dAck, and then look into the IDE controller, possibly an LCD, etc.
I'm too stupid to cope with more than one type of processor/embedded controller so I am resigned to wait and see if MATTTCATTT can get the MUCOP pic based device to work.
I think we are going to have to take up a collection to get him that missing crystal. I'd mail him one but I think postage would cost more than the crystal (big grin)
I think we are going to have to take up a collection to get him that missing crystal. I'd mail him one but I think postage would cost more than the crystal (big grin)
).
An externally hosted image should be here but it was not working when we last tested it.
http://www.ueno.no-ip.org/~tube-audio/DAC/atapi_ctl/
Another Version Of CD-Rom Player From Japan...
http://babelfish.altavista.com/
You can use Web Translation From Japanese to English...
Download Source Code
You can use Web Translation From Japanese to English...
Download Source Code
My project is almost finished and works fine. Here are some pics with the test board. I'm making a final board now with a cleaner layout. The uC is a PIC and the software supports front buttons, 2x16 display and RC5 remote - almost all functions. Also supports 2 cdrom units on the same cable (master/slave).
Attachments
ok, i've spent most of the night reading this thread start to finish (did it over 2 sessions!). Some interesting ideas, I may try to implement the controller in VHDL, as I have never got the hang of accurate timing output with a uC. May use a PIC and the available C code for the display though.
I like the idea of reading the CD at higher than 1x speed into a buffer, I wouldn't imagine this to be too hard in a CPLD/FPGA as the core logic speed should be much greater than the data rate.
Matt
I like the idea of reading the CD at higher than 1x speed into a buffer, I wouldn't imagine this to be too hard in a CPLD/FPGA as the core logic speed should be much greater than the data rate.
Matt
