I know there are many people talk about 2nd handed CDROM as transport before, but I want to mention again, because the price is DAMN CHEAP and the sound is DAMN GOOD.
1.The CDROM must have playback bottom on front panel
2.The CDROM must have digital(spdif) output on rear panel, remember, don't use the analog output.
Sony' Asus' Benq 52x cdrom are both good choice.
3.In order to have great sound, you must have a great power supply, and the best power supply is the power supply in the 5.25" SCSI external box, the SCSI or IDE interface is useless here, so tear all interface apart.
4.Put the CDROM into the box and connect the power source, the following step is most important, there is a pair of RCA jack on rear panel, use one of them as the digital output (coaxial).
It cost me only USD$10 to have this CDROM transport, but the digital sound is much better then my Marantz CDP.
1.The CDROM must have playback bottom on front panel
An externally hosted image should be here but it was not working when we last tested it.
2.The CDROM must have digital(spdif) output on rear panel, remember, don't use the analog output.
An externally hosted image should be here but it was not working when we last tested it.
Sony' Asus' Benq 52x cdrom are both good choice.
3.In order to have great sound, you must have a great power supply, and the best power supply is the power supply in the 5.25" SCSI external box, the SCSI or IDE interface is useless here, so tear all interface apart.
An externally hosted image should be here but it was not working when we last tested it.
4.Put the CDROM into the box and connect the power source, the following step is most important, there is a pair of RCA jack on rear panel, use one of them as the digital output (coaxial).
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
It cost me only USD$10 to have this CDROM transport, but the digital sound is much better then my Marantz CDP.
The sound will not be decent, because those drives cannot play data at 1x speed properly. Audio signal with no controller, no buffer, will have a VERY high amount of jitter.
It was 1995 when I did try it the first time, with a CLV drive (with less than 12x maximum speed) and still sucked... You can find now exclusivelly Zone-CAV drives.
PS: That plastic think that you press on it is called "button", not "bottom".
It was 1995 when I did try it the first time, with a CLV drive (with less than 12x maximum speed) and still sucked... You can find now exclusivelly Zone-CAV drives.
PS: That plastic think that you press on it is called "button", not "bottom".
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PS: That thing you press is actually a thing not a think.
No that think is not a thing or a button but an actuator
Reviving this thread because I have a similar project in the works.
I have a CDROM with the player functions in front and a digital audio output in back which outputs SPDIF. I plan to make a basic enclosure for it with a digital RCA out to plug into my DAC. Later on I might include an analog output stage but this is fine for now.
One question about the digital out. Is it fine to wire the digital out directly to the RCA coax or do I need some sort of circuit in between the digital out and RCA connector?
EDIT:
Also for those of you that doubt that a CDROM could be a good digital source, here is what one guy found when measuring the SPDIF signal of various CD Players.
http://www.jacquesstompboxes.com/oscillo.htm
The ASUS DVD-ROM actually measures really really well.
I have a CDROM with the player functions in front and a digital audio output in back which outputs SPDIF. I plan to make a basic enclosure for it with a digital RCA out to plug into my DAC. Later on I might include an analog output stage but this is fine for now.
One question about the digital out. Is it fine to wire the digital out directly to the RCA coax or do I need some sort of circuit in between the digital out and RCA connector?
EDIT:
Also for those of you that doubt that a CDROM could be a good digital source, here is what one guy found when measuring the SPDIF signal of various CD Players.
http://www.jacquesstompboxes.com/oscillo.htm
The ASUS DVD-ROM actually measures really really well.
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What does TTL mean? Is it basically the same as SPDIF but the voltage is higher? In that case would I just have to add a resistor?
Quite fun watching people try and correlate what the square wave looks like to the resultant sound field that comes out of the DAC
The main thing is to use twisted pair cable to the RCA connecter or co-ax so the signal and its return are always in intimate proximity to each other....
No argument from me that the main determination of sound is in the DAC. Which is why I am going with a basic CD/DVD-ROM instead of some expensive transport. If the signal is bad enough though then it could produce errors and the link I posted was to show that a DVD-ROM can produce a clean signal.
Thanks for the cable recommendation.
Try this--
An externally hosted image should be here but it was not working when we last tested it.
Good sounding transports-
Asus DVD-E818AAT
Compaq CDROM LTN-486S
How can a transport sound good, or different...From the CD to the DAC it is a digital signal stream, and basic digital signal transfer, so if the interface is engineered correctly and the drive reads the CD correctly then the data presented to the DAC would be the same for any correctly working transport. The interface should be looked at as digital signal transfer and engineered accordingly...
I'm afraid is not so simple. Re-clocking will not help too much if you do not buffer enough data and if you buffer you get into another issues.
Regards,
Tibi
Good joke !
Such things have been largely discussed on this forum.
I suggest you to start by comparing different units (able to provide bit accurate stream). If the system will be performant enough, for sure you'll be able to hear consistent differences between them.
Regards,
Tibi
It was not a joke....
Yes they have been discussed add nauseum, never seen any proper testing only anecdotes, I hear this I hear that....yet in other fields of electronics (obviously not as cutting edge as audio reproduction) these problems can be solved, including the effects of jitter. Again its a pretty mundane digital interface, not very high data rate, being transported maybe a metre down a cable... re-clock at the DAC if jitter is the problem. As stated other less cutting edge areas of electronics I have worked in as part of a team solve these problems, these are such areas as military communications, phase array radar etc etc.
Audio reproduction has its problems like all fields of electronics but I believe in some cases they are over exaggerated to the extreme and jitter levels is one of them IMO.
Yes they have been discussed add nauseum, never seen any proper testing only anecdotes, I hear this I hear that....yet in other fields of electronics (obviously not as cutting edge as audio reproduction) these problems can be solved, including the effects of jitter. Again its a pretty mundane digital interface, not very high data rate, being transported maybe a metre down a cable... re-clock at the DAC if jitter is the problem. As stated other less cutting edge areas of electronics I have worked in as part of a team solve these problems, these are such areas as military communications, phase array radar etc etc.
Audio reproduction has its problems like all fields of electronics but I believe in some cases they are over exaggerated to the extreme and jitter levels is one of them IMO.
To demonstrate something I always start by observation. I suggested to you to do the same, but it's up to you. The point of looking for a good CD transport is because this make a difference.
On other hand Jitter can have different spectrum affecting DAC operation is so many ways. A PLL loop may help in some cases and can be useless in others. The market is full with different approaches. None is perfect and will sound different from source to source.
Jitter is not a voodoo, it's very present in data communications and on every CD optical unit.
I spent some time looking into such issue and my choice is a CD transport able to extract all data from CD with the lowest possible error correction.
On other hand Jitter can have different spectrum affecting DAC operation is so many ways. A PLL loop may help in some cases and can be useless in others. The market is full with different approaches. None is perfect and will sound different from source to source.
Jitter is not a voodoo, it's very present in data communications and on every CD optical unit.
I spent some time looking into such issue and my choice is a CD transport able to extract all data from CD with the lowest possible error correction.
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