What's the deal with CD player's used as transports?

[nicholtl]

From my understanding, CD players/multichangers can be used 1 of 2 ways.

1) As a transport.

2) As a player utilizing it's own internal DAC's.

As such, this basically means that by using digital interconnects (optical or coaxial) between the CD player and the receiver/preamp, the CD player is thus qualified as a "transport." If, on the other hand, the CD player is connected via analog interconnects (RCA or XLR), then you will be utlizing the CD's own internal DAC's.

This being true, and I don't know if it is, but wouldn't that mean no matter what level a CD player is ($60-$25,000), connecting it with a digital cable would make it all sound the same, since all signal processing would be taken charge of by the receiver/preamp? Becaues if that's the case, why would ANYONE with a high-end CD player use it as a transport? Wouldn't they simply be better off using the CD player's own, internal circuitry to produce sound?

And along these same lines, wouldn't that mean any DVD player, SACD player, or DVD-A player connected with a digital cable produce the same results? Identical sound compared to another player connected to the same receiver/preamp??

I am really quite confused on this subject, and if someone can shed a little light on it I'd be much obliged.

[mikepinkerton]

I asked this same question over on the avsforum and the general response was that at a certain quality level, this is correct, but cheap equipment can produce results of varying quality (introducing jitter, etc).

I'd love to see other responses as well.
-Mike

[Aussie Geoff]

Hi,

I used to think that 1s and 0s were 1s and 0s (wishful thinking) and then (prompted by my inquisative nature) I tried comparative listenning and found that even with a digital link:
1) Transports vary and make a big difference in sound (CD players and DVD players, especially when playing CDs)
2) Digital Cables make a difference.
Hence my investing in a high quality CD player even for the digital link.

There are lots of posts and research articles to do with the effects of jitter on audible distortion etc - but bottom line - until you get to quite expensive CD players and even more expensive DVD players - IMO you can easily hear the difference between them as digital transports except on special DACs that resycronize the digital signals, eliminate jitter etc...

Geoff

[nicholtl]

Very interesting. You see, I currently use the M333ES Sony 400 CD megachanger as my CD player, which is connected to my C2 with a very high quality toslink cable. But CD's on this unit sound VASTLY different than when played on my Denon 3800 DVD player, which is connected utilizing a very high quality coaxial cable. I don't consider either of these units to be uber high end, but they are not exactly lo-fi units either.

In a week's time I'm getting a Classe CDP-10 delivered to my door, and I've already anticipated using XLR cables to connect these. I assume that since this player retails for $2000, using the internal DAC's would be preferable to making it a "transport" by connecting it via toslink or coaxial.

And yet...it is quite apparent that even "transports" have inherently different sound.

[Aussie Geoff]

Nicholt,

I think you have answered your own question with what I have found to be the best test of all "your ears". All the should it or should it theory can be confirmed ir blown away by listenning.

A thought for you - swap the coax cable onto the CD player and compare - with a lot of units you can have both plugged in to the CD and use two different processor / reciever ports for a quick change - it is often a revelation as to how different the two digital cables sound. Now try the reverse with the DVD player... I went down this path and ended up (happily) replacing all by digital cables...

When you get your new CD player - I would suggest trying Analog, and Coax and TosLink and seeing which you like best. I ended up with Analog and Coax - Analog for some pure stereo work and Coax for everything else!

Geoff

[Kevin P]

One thing that the analog vs. digital (transport) comparison brings out is the difference in the DACs in your source device and your processor. Therefore, one won't always be better than the other, depending on your gear. Assuming analog bypass is always used for analog mode, a high-end CD player run through a $250 Sony receiver will most likely sound better connected via analog than digital, whereas if you have a $60 player connected to a $3k pre-pro, the digital connection will likely sound better since (hopefully) the $3k pre-pro has higher quality DACs than the $60 player. With higher-end gear used for both the transport and processor, the differences will be more subtle but still there, and which option you choose could simply be a matter of personal taste.

As for the difference between coax and optical, note that most gear's optical interfaces are cheaply implemented, and most Toslink cables are cheap plastic fiber (a rare exception being Doug's limited-edition glass fiber cable). Thus, in most applications, coax will sound better.

As for what differences a quality digital coax cable can make, just check out the reviews in the CAT Cables forum.

P.S. Like Aussie, I too use analog for CD and SACD playback, since my DVP-S9000ES has better sounding DACs than my Outlaw 1050, and use the digital coax for DVDs.

[nicholtl]

Good stuff, I think you guys are very right. I should simply just conduct my own little demo and see for myself, once and for all, what the difference in sonics are between digital cables, and how they fare against pure balanced analog cables.

By the way, when you guys state that I should connect a CD player or DVD player via coax/toslink AND analog, so as to allow me to switch back and forth on the fly, is that accomplished by plugging both types of cable into the source component, and then inputting them into different inputs on the pre/pro, such as "CD" and "DVD?" I did not know/realize a source component could output sound from both digital and analog at the same exact time?

[Kevin P]

...is that accomplished by plugging both types of cable into the source component, and then inputting them into different inputs on the pre/pro, such as "CD" and "DVD?" I did not know/realize a source component could output sound from both digital and analog at the same exact time?

Every source device I've seen output the signal to both the analog and digital outputs at the same time. I've never seen one that makes you choose one or the other, except on the video outputs. Some inexpensive progressive-scan DVD players will disable the composite and S-video outputs if you select progressive on the component output. I've also seen DVD players (older Pioneers) that have a switch to choose between S-video and component.

But for audio, the digital and analog outputs are always active, with the exception of DVD-Audio or SACD where only the analog is active, thanks to the overly paranoid media companies.

[mikepinkerton]

I'm baffled at how different optical cables can have a different sound. Heck, I'm only slightly less baffled at how 2 digital coax cables can have a different sound. Isn't that like saying OTA HD picture quality depends on the quality of your UHF antenna?

What am I missing?
-Mike

[nicholtl]

Hmm, that might be a worthwhile audition actually. Maybe I'll try it once I unhook all my gear upon arrival of all my upgrades. We'll get to the bottom of this...