I hadn't even realised that we were attempting to copy Meridian (although doing something better than them would be nice!
)The fact and all the excitment is, in my eyes, that a CDROM drive is capable of getting all of the data off a reasonably-unscratched CD - PCs do it all the time with data .OK, we've established that it will require a bit (well, you know...) of work, but the long and the short of it all is that it is theoretically possible to create a 'perfect' and fully-customisable CD transport from a drive costing £30. Isn't that just cool?
It seems that the most 'hardcore' work in this project will have to be in creating ECC checking and re-reading routines for the controller. This is possible, definitely (a PC can do it), though I have no idea how much effort it will take. Once someone looks up the standard drive commands/interfaces, I don't see how an experienced programmer could have a whole lot of trouble creating this, but I'll say again that I don't really know.
Is there anyone still on here who isn't opposed to doing the controller themselves? I just don't see any area where it's amazingly complex.
i have reproduced the circuit design from the mucop site, but the network card has died on my other pc, so i cannot connect to the internet. i will post it when i can.
i have also purchased the parts, and i should be able to test the results in the next week or so.
total cost so far:
cd-rom: free
parts: ~£3
i have also purchased the parts, and i should be able to test the results in the next week or so.
total cost so far:
cd-rom: free
parts: ~£3
Konnichiwa,
Only under software control from an external controller. Just actually read the source code for one of the better "Exact Audio" Rippers to see what is involved.
Well, I'm not sure I'd call it "cool". But yes, it is doable. My own investigations into the subject led me towards a HTPC and for fun to tinkering with a stripped down NEC602, which already has a display and drive controls pluys you can easily inject a decent external clock, as you can actually still find the clock on the drive....
Yes, but HONEST, the easiest approach is simply to take a PC of the PentiumII/III Class minimum and "silence" it, plus add suitable software.
There are however in this day and age excellent HTPC Cases and Barebones around, worth investigating....
It is not too complex, BUT it has been noted that with a single uP/PIC we are hitting speed barriers among other issues. It would be great however to have a simple controller that takes any IDE Drive and creates I2S, S/P-DIF & AES/EBU outputs with a further BNC "clock" Input for an external master clock.
Or again, another option would be to add Guido's VCXO based re-clocker and a memory buffer after the on-board S/P-DIF section of the CD-Rom. With a VCXO having only a few samples in memory will be fine.
Sayonara
Wingfeather said:
Only under software control from an external controller. Just actually read the source code for one of the better "Exact Audio" Rippers to see what is involved.
Wingfeather said:
Well, I'm not sure I'd call it "cool". But yes, it is doable. My own investigations into the subject led me towards a HTPC and for fun to tinkering with a stripped down NEC602, which already has a display and drive controls pluys you can easily inject a decent external clock, as you can actually still find the clock on the drive....
Wingfeather said:
Yes, but HONEST, the easiest approach is simply to take a PC of the PentiumII/III Class minimum and "silence" it, plus add suitable software.
There are however in this day and age excellent HTPC Cases and Barebones around, worth investigating....
Wingfeather said:
It is not too complex, BUT it has been noted that with a single uP/PIC we are hitting speed barriers among other issues. It would be great however to have a simple controller that takes any IDE Drive and creates I2S, S/P-DIF & AES/EBU outputs with a further BNC "clock" Input for an external master clock.
Or again, another option would be to add Guido's VCXO based re-clocker and a memory buffer after the on-board S/P-DIF section of the CD-Rom. With a VCXO having only a few samples in memory will be fine.
Sayonara
I have got the schematics from the other pc, and i will post them now. my prototype uses/will use a PIC16F84 microprocessor made by microchip, and about 10 other components.
The original ciruit, from http://private.addcom.de/KeithWilson/Projects/mucop.htm can be found here: http://private.addcom.de/KeithWilson/Documentation/MuCoP/DesignGuidePic.zip
I have posted my representation of the circuit.
The original ciruit, from http://private.addcom.de/KeithWilson/Projects/mucop.htm can be found here: http://private.addcom.de/KeithWilson/Documentation/MuCoP/DesignGuidePic.zip
I have posted my representation of the circuit.
Attachments
If I may ask what you guys think of the following!?
http://www.tadara.com/items-id=9445.htm
thank you
http://www.tadara.com/items-id=9445.htm
thank you
Mattcatt, in your schematic couldn't be 16F84 (only 18 pins). Anyway I'm working on a version with 16F8xx that supports LCD display and remote. The first attempt of sound will be with AD1892 receiver with some reclocking.
The ATA specs are really a mess; I hope I can transform data into I2S with a help of a CPLD; otherwise a DSP will be the only alternative to make a good standalone CD.
The ATA specs are really a mess; I hope I can transform data into I2S with a help of a CPLD; otherwise a DSP will be the only alternative to make a good standalone CD.
Clock division for CD ROM transport
I Picked up a cheap NEC CDR500 CD ROM drive at the weekend (SCSI). I have already taken it to pieces- a nice aluminium cast assembly like a CD-PRO mechanism. Unfortunately I was not too observant and there is no S/PDIF out! Looking on the board I have found a TDA1545A (with I2S bus). I wish to use the I2S, together with a CS8402A to provide me with a nice S/PDIF output so I can use with a variety of equipment (I know it is not the ultimate!) Of course I am going to reclock the transport. Currently the clock operates at 384 x fs (44100). However the Crystal Semiconductor transmitter only operates at 256 x fs
My question to others is- will a divide by 1.5 clock divider circuit (using flip flops and logic) result in significant jitter? Is there an alternate transmitter on the market that will operate from 384 x fs (44100) ?
I Picked up a cheap NEC CDR500 CD ROM drive at the weekend (SCSI). I have already taken it to pieces- a nice aluminium cast assembly like a CD-PRO mechanism. Unfortunately I was not too observant and there is no S/PDIF out! Looking on the board I have found a TDA1545A (with I2S bus). I wish to use the I2S, together with a CS8402A to provide me with a nice S/PDIF output so I can use with a variety of equipment (I know it is not the ultimate!) Of course I am going to reclock the transport. Currently the clock operates at 384 x fs (44100). However the Crystal Semiconductor transmitter only operates at 256 x fs
My question to others is- will a divide by 1.5 clock divider circuit (using flip flops and logic) result in significant jitter? Is there an alternate transmitter on the market that will operate from 384 x fs (44100) ?
Re: Clock division for CD ROM transport
AKM AK4101/AK4103
TI DIT4096/DIT4192
ray.
Oli said:I Picked up a cheap NEC CDR500 CD ROM drive at the weekend (SCSI). I have already taken it to pieces- a nice aluminium cast assembly like a CD-PRO mechanism. Unfortunately I was not too observant and there is no S/PDIF out! Looking on the board I have found a TDA1545A (with I2S bus). I wish to use the I2S, together with a CS8402A to provide me with a nice S/PDIF output so I can use with a variety of equipment (I know it is not the ultimate!) Of course I am going to reclock the transport. Currently the clock operates at 384 x fs (44100). However the Crystal Semiconductor transmitter only operates at 256 x fs
My question to others is- will a divide by 1.5 clock divider circuit (using flip flops and logic) result in significant jitter? Is there an alternate transmitter on the market that will operate from 384 x fs (44100) ?
AKM AK4101/AK4103
TI DIT4096/DIT4192
ray.
Fashion? Dogma? Satan uses a dac with a built-in filter?Matttcattt said:
Not a tutorial and based on rather old IC's, Analog Devices' AN-394 application note gives a useful insight into the design of a dac and AN-283 covers the bitstream type dacs, the type of dac ic that usually comes with a built-in filter.
You might also find this useful
http://members.chello.nl/~m.heijligers/DAChtml/dactop.htm
ray