How important is transport quality to CD playback?

I have always looked sceptically at claims that a given CD transport imposed some sort of sonic signature on the final reproduced sound. For some background, I work in the software industry, and am well aware of the devastating effect even one bad bit can impose on a piece of data or an executable program. Given the computing world's sensitivity to absolute data purity, there seems to be no issue with using cheap, even sub-$20 CD drives to handle programs and data files. I reasoned that if these cheap drives can easily provide high levels of data integrity, what would the real benefit of a $2000 CD transport be?

I realize that CD mechanisms implement a form of error-detection and correction, which can result in re-reading sections of the data from the disc. In a computer these re-reads may make things seem slow to the user, but if successful they have no truly detrimental effect. In contrast the real-time nature of CD playback will result in audible stutter and skipping if re-reads become excessive. However, if you are not experiencing these very audible and unmistakable symptoms, the data stream is accurate and should impart no other sonic effects on the reproduced sound.

Today, however I read the following statement in a link posted by clint e.

"With far less error correction – even zero error correction – the servos in the CD player’s optical laser block are not generating excessive electrical noise; on a regular CD they are constantly working to eliminate bit errors. This purity of signal is undoubtedly beneficial to audio quality." - Eric Kingdon, Sony UK

Now this statement is finally something that makes sense to me... sorta. It makes sense that the analog sections of a CD player could be affected by electrical noise generated by the action of the servos in the pickup mechanism. So logically, a high quality disc played in a high quality mechanism, would reduce this servo-induced noise in the analog circuits and result in improved audio quality. Well built power supplies with separate digital and analog sections, and smart chassis layout would also logically help in this regard.

However... I still don't see how this makes much difference when using a separate DAC and transport, but it does explain why using an external DAC often results in better sound quality over a single-unit CD player. With the laser mechanism in a separate chassis and having its own power supply, the DACs and analog circuits are completely isolated from this servo-induced noise. This is especially true if using an optical cable between transport and DAC.

My own experience using a variety of "transports" confirms to me that when using a separate DAC, the quality of the transport is almost irrelevant. In my home office system I currently use a Marantz DV6001 DVD player as a transport into my PS Audio Ultralink Two DAC. I use it for a few reasons, chief among them being that it can play loads of different formats and output them all as a PCM digital signal that my DAC handles well. It also compliments the cosmetics of the PS Audio gear quite well. However, I have also used a Marantz DV4001, an Adcom GCD-575, a Cyberhome CH-DVD 405 (which has a computer DVD drive inside), and a super cheap $30 Cyberhome DVD player as a transport and ALL of them sounded identical to my ears when their digital output was processed by the PS Audio DAC.

So while I understand how the quality of the CD mechanism can affect stand-alone CD players, and how this also explains why a separate transport/DAC setup has advantages, I still feel that when using a separate DAC, even a low quality transport can be used without ill effects.

Thoughts???

Rob

I agree with that statement, I have listened to dingus's system and my own with similar results, imo, dingus uses a wadia transport and we used a cheaper player "cant remember what it was" and we did an A+B comparison, and I could not hear much, if any difference in sound quality, We used coax and digital outputs to his DAC.

on my own system, I use a decent Marantz cd 67se which from what I have read is a decent player, my other cd/dvd/mp3, panasonic 49.95 special works great for all those applications. I run both of those players through my Zhaolu DAC using a coax and optical cabling, and I cannot hear a difference in sound.

My Hypothesis, "I have never used that word before" is that 1's and 0's are just that. and the cd player reads those and sends them to the DAC. I can believe that during conversion from 1's / 0's internally in a cd player to its internal DAC, that there could be flutter/electrical noise/distortion from all the working components while converting to analog, which might degrade the sound quality during listening.

elroy

i was expecting a night-and-day difference when i went to a dedicated transport, but as Todd noted any difference over a cd player being used as a trasport were razor thin if any. using the same cd player as a stand-alone player against the transport/DAC combo was a night-and-day experience, so the primary component in this case would appear to be the DAC. what really did make the difference for me with the Wadia transport is using an ST glass optical cable. its a clear step up over a toslink or coax cable.

Does a good power supply, a good cd mechanism and a solid case worth all the money they want us to pay to hear music in hi-fi ?
I concur with everything Rob says, and maybe that’s the reason why my actually main audio transport is a Plextor dvd rom with an outboard USB Dac. In resume, my computer.
....and please, let's not talk about jitter, because i CAN'T ear it!!!

Attached Image (Click thumbnail to expand)

I am glad to hear that I am not alone in my thinking on this. I definitely think that a good outboard DAC can make a huge difference in the way a system sounds, and I have been very happy with the PS Audio Ultralink Two (I think it was a Stereophile class A component back in the mid-90s). I was also happy with the Adcom GDA-600 I had for a while. However, I just can't justify the price that some vendors charge for a supposedly "high-end" transport.

Does anyone have an opposing view?

Rob

thats why i got mine on the used market.

thats why i got mine on the used market.

unless one fell in my lap, like if dingus decided to give me his, I wouldnt pay the money for one, I just dont think the the money paid is worth no better sound gain.

now if I was rich, well thats another story, as a matter of fact i wouldnt even lower myself to this teeny web site, i'd be somewhere that my rich snobbish attitude would work, like AK

elroy

Whooosh!

Dingus and I tested the effect of transports and their power supplies on the sound quality of CD playback a couple of years ago. We used one of Dingus's CD players, his EAD DAC and my Yamaha CDX-10000 CD player. The Yamaha CDX-10000 transport through the EAD very clearly outperformed his CD player through the EAD. The CDX-10000's DAC also beat the EAD. It certainly didn't embarrass the EAD, but to my ears the CDX-10000's DAC sounded smoother and less grainy. I was actually quite impressed by the sound quality of the EAD.

well shoot. i thought i had posted the results of this session, but if so i am not finding it. anyway, the part that has stayed in my memory is that the CDX-10000 on its own was better than the EAD DAC/Luxman d-113 combo, though as Mark said it was not a stark difference. i vaguely recall hooking the CDX-10000 up to the EAD, but that the EAD offered it no advantage.

I am not surprised that the CDX-10000 performed well. Looking at pictures it appears to be constructed as two very well built units in one chassis. Exactly what is necessary for a great standalone player.

I would have loved to have heard the comparison of the two units performing as transports for the EAD, to see if I could also hear the difference between the two. I don't have a unit of that quality to test against. My Adcom GCD-750 only has a digital input (so it can be used as a DAC), but no output. Perhaps I could try the Marantz DV7001 from my HT system. I want to believe that a high-end transport would make an audible improvement (because I would love to justify something like an EAD T-1000 or PS Audio Lambda), but until I hear it, I remain skeptical.

Rob

if i am not mistaken, the EAD is a budget minded DAC, I would only assume that a more middle of the road DAC like the ones we are all using might make a bit of a difference, but I have nothing to prove that.

elroy

The EAD DAC that I was referring to is Dingus's main DAC, the EAD DSP 1000 -- hardly a budget model.

This post has been edited by Mark B on June 26, 2009 01:44 pm

well shoot. i thought i had posted the results of this session, but if so i am not finding it. anyway, the part that has stayed in my memory is that the CDX-10000 on its own was better than the EAD DAC/Luxman d-113 combo, though as Mark said it was not a stark difference. i vaguely recall hooking the CDX-10000 up to the EAD, but that the EAD offered it no advantage.

Here's a link to post that I made following the A/B/X testing. The CDP you brought down was your Denon, not the Luxman.

yeah, i knew my memory was faulty on this one, heck i dont even remember having the Denon at your place.