CD Transport-optical out/external dac

RuSsMaN · May 2002

Just looking for your thoughts on the subject, I have no opinion at this point.....

Is a transport a transport? Basically, if one is to use the optical 'out' on a cd player (bypassing internal dacs), what other features/specs of the transport are important? What should one look for when choosing a 'transport'.

Using an external dac, are there big differences in the laser assembly, motor(s) and what not? Will there be a big (sonic) difference in, say a Technics single disc and a Marantz using an optical cable with the same external dac?

Cheers,
Curious Russ

TroyD · May 2002

I've sort of been wondering the same thing to be honest.....

This may be a stretch, but would it be somewhat like using a receiver as a preamp ???

BDT

nascarmann · May 2002

Unpacking almost over, so I have some time to post a little!

This may be a stretch, but would it be somewhat like using a receiver as a preamp ???

No, I don't think that is a stretch. I use digital out of the CD and then let my Yamaha's DAC's convert to analog and send to the amp's. So, IMO an external DAC would be very close to the same. To answer Russ, First when you say "transport", do you mean the way the digital signal is moved fron the CD to the external DAC? And when you ask about the Technics and Marantz, would not the quality of the laser "sending" the signal have a most to do with the quality of reproduction? Shitzski, I have really never gave this any hard thoughts? Not sure why you are asking with the cd8b?? That unit has great DAC's in it? Or am I missing something in this? Hell I don't know! All I do know is I have had the Corona's on ice know for about 2hrs and it's time to have a few! Just damn glad to be back home for good??:D

RuSsMaN · May 2002

You read me right on your first two points, Troy has the AMC CD8b, I'm using the ADC 16/2r.

Just pondering, a local electronics closeout shop has a single disc Technics with optical out, new in box for $44...... Model SL-PG4 I think.....

Cheers,
'Ready to get my drink on' Russ

nascarmann · May 2002

'Ready to get my drink on' Russ

Yah, me too! This may be my last post sober today

Sounds like a good deal too me on the Technics?

raycomics · May 2002

First of all, I don't know a thing bout how internal vs external DACs work. What I do know from experience is that, to my untrained, non-audiophile, Joe Sixpack Ears, Coaxial Digital sounds a whole lot better that Optical Digital. Coaxial provides me with a Depth to the music, where as Optical just refines the Height and Width.

I am not saying this to spark a debate, just thowing in my un-audio educated $.02.

joe logston · May 2002

i use a sony dv-7000 as a transport. all it dose is read the digital information on the cd and transfer it though my optical toslink cable to my receivers dac and it works great, so all it depends how good the transport is, i dont know about the technics player russ, but you cant beat the price. 'wow' all the transport means is transfer the raw digital signal to a seperate dacs from the internal dacs on the player.

stubby · May 2002

From what I understand, you want a transport with a good solid tray mechanism, a stable "platter", and a nice quality lens for the laser. Anything to add stability for good tracking.
The dac is really subjective. Everyone has their own idea for what sounds "right". Some give warmth, some are purely accurate, blah, blah, blah. I think on many of these it would require a true golden ear. I don't fall in that category.

Stubby

madmax · May 2002

This may be a little stretch but a transport would be kind of like a turntable without a cartridge. They came in all varieties. Cheap ones had more wow and flutter, ligher weight bases and less precision tone arms. If you put the same high quality cartridge in a cheap one vs a good one you could really tell the difference. You could stretch it a little further and compare the cartridge to the DAC. If the cartridge was a cheap one it probably wouldn't matter what the quality of the turntable but if it was a really good cartridge then quality of the table would make a big difference.
As far as a transport vs a using a CD player data output, they perform the same function. They both read the data off the disc and supply it to the DAC. Each byte is placed in three different places on the disc, is read 3 times then the DAC determines what the byte is. That way if it misses one due to a mis-read then it throws that one out. If it misses two then it makes a guess. Speed is not very important so long as it is fast enough and the average speed is correct so a buffer is not overrun. Jitter is an issue as well but I don't have a good handle on that. I think it has to do with the data timing changing mid byte and not matching what is expected by the DAC but I'm not really sure. If anyone knows let me know.
A transport that does not read well will miss a certain amout of data and will still sound good. The problem is when the DAC starts guessing about more and more bytes it will at some point no longer be accurate even though it is still playing. (a higher amount of bytes are in the "guess" state) So... there is a range of quality which produces a range of accuracy.
madmax

TroyD · May 2002

I'm probably in Stubby's category.....I think that the law of diminishing returns really comes into play here. For 175 bones the new cd player that I got is light years ahead of the old POS that i was using......but let's say I go out and drop (insert figure) for a DAC, discounting the placebo effect, how much REAL improvement is there?

I dunno....I'd really like to get some good demo in on this subject.

Chief Whisperfromrectum

CD Transport-optical out/external dac

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