CD transport wars and an unexpected realization regarding CD copies.

Hello and welcome! This was somehow a difficult post for me. By difficult I don't mean that the testing was difficult; it is the results that me and Panos got that made my Hi-Fi life miserable and lead to more and more of testing. I also have to admit that before our testing, when I was reading similar things like these I am about to write, I was granting the author as a deaf psycho.

CD transports, do they make a difference?

Everything started the other day due to a Pioneer PD-75 CD player that was for sale at eBay. I was telling Panos that I would love to get one for a transport just because I admire the built quality inside it; Panos asked my opinion about the role of a CD transport, I said that I assume that the Pioneer PD-S707 we both have are good enough and as it usually happens, this was the beginning of some blind tests.



A naked Pioneer PD-75 transport view.

So we started by comparing a humble Sony PS2 slim Vs. the Pioneer PD-S707, both acting as CD transports, digitally connected to a Parasound D/AC-1500 DAC. All the transports were connected with optical TosLink -  I know that many consider TosLink inferior of digital coaxial, but as I have stated in this post, our tests did not proved so.

By just changing the digital input on the Parasound, we would get an easy A/B instant comparison between the two transports. Personally I believed that the Pioneer with its stable platter mechanism would simply behave better.

From top to bottom: PS2 slim, Pioneer PD-S707 and Parasound D/AC-1500.

For the test we needed two units of the same CD album; we had to make the transports reproduce the same thing simultaneously. We choose to use Vivaldi: Allegro from The Four Seasons: Spring (Jacques Loussier Trio) from a TELARC CD, however one of the CDs was a copy made at my Alesys Masterlink ML-9600 studio CD recorder, a recorder that I trust for giving an exact copy of the original CD. Yes, I know, but bear with me for a while...

As always our test was blind, meaning one of us was changing the digital input at the Parasound DAC and the other was listening, without knowing what is that he is listening to. So we hit Play simultaneously at the two transports and the blind test began. To my horror, the PS2 was sounding better than the Pioneer! (By better I mean that the sound stage was wider and deeper, without loosing any focus).

However, it then hit me; are we really listening to sound differences that are caused by the transports or the fact that one of the CD album was a copy is messing the test? The copy was at the PS2, the original was at the Pioneer, I suggested to exchange the CDs, Panos laughed but the blind test was eventually repeated.

To my delight, results were flipped; it was now the Pioneer sounding better. But wait a minute, that means that we preferred listening to the CD copy? How is that possible?!? I would never expect to say this but yes, the CD copy that was made at the Alesys CD recorder was sounding better; the sound stage was bigger, more spatial and had a better sense of space detail. The difference was small but not minor.

Note: I had read about this several times in CD recorder reviews and laughed. I mean, how is it possible to make a copy that sounds better than the original? Is the CD recorder adding details in the music? But now that I have witnessed this phenomenon myself, I have to accept it and try to explain it. First of all,  I have to assume that a CD recorder can not add anything; the details are there, it is just that the CD player is not reproducing them, whereas the CD recorder can read them (keep in mind that the Alesys is using an HDD to transfer the tracks there before recording them on the CD, so we do have some kind of a buffer). Then, the CD recorder manages somehow to make a better (or more "CD transport compatible") recording on the CD, so when the CD transport reads it, it can now extract things that couldn't be extracted in the first place. Still, all these are just assumptions. More at the end of the post.




The albums used at the test, the one on the bottom left is actually a copy.

However, we were not done yet. We continued by comparing the Pioneer PD-S707 with a Philips CDR 950 and a Pioneer PD-S507 (always acting as CD transports and now using two original, identical CD albums "USHER The Diamond Revolution", track 11, which is an orchestral version of Alla Turca of Wolfgang Amadeus Mozart) We called it even; all the CD players when used as transports were sounding the same.

Then, again by using these two original and identical CD albums we compared the PS2 with the Pioneer PD-S707 and the Pioneer lost. Damn! Maybe the two albums we were using had a kind of a mysterious hidden difference? Maybe one digital optical path of the Parasound DAC developed some kind of fault over time that degraded its performance? We completely reversed the digital connections, we exchanged the albums between the players and we repeated the blind testing. There was no doubt: PS2 was a better CD transport than the Pioneer PD-S707 (or the PD-S507 or the Philips CDR950). Damn again! My Hi-Fi world just collided...



Our two original TELARC sample CDs.

After a couple of days, Panos came to my home in order to make a blind test between my Sony PS3 fat Vs. my Pioneer PD-S707, both again acting as transports, digitally connected with an optical TosLink fiber to my modified and most revealing Parasound D-AC/1000 DAC. This time we used another CD album, a TELARC sample that Panos has twice. We choose Il Trovatore: "Vedi! le fosche notturne spoglie" from Act II, Giuseppe Verdi.  What we noted was that the sound was different, but just that; we couldn't say that one transport was sounding better than the other. The sound coming from the PS3 had just a slight idea of more treble. It was not harsh neither more detailed. Practically, the sound quality was even. PS2 still appeared that was the king of transports.

An Accuphase beauty on the rescue.

A few days passed and I was thinking about the results. Is the PS2 such a wonderful transport and/or the Pioneer total crap? I turned to my friend George for rescue; he is the owner of a much appreciated 16.6kg Accuphase DP-500 CD player. He kindly borrowed us his beast in order to make more blind testing. I took the Accuphase to Pano's hone and the blind testing started. First battle was between the Pioneer and the Accuphase transports. At the beginning we used the original and the copy "Allegro from The Four Seasons: Spring" (Jacques Loussier Trio) from the TELARC CD, we wanted to find out if with this set up we would still continue to prefer the copy CD. Eventually no matter which transport was playing the copy, we couldn't distinguish any difference in sound quality.


Accuphase DP-500 and Pioneer PD-S707 waiting to be compared as transports.

Then we moved to the two identical USHER CD albums, again results were even: we couldn't distinguish one transport from the other. 

Yes, we are a bit ashamed to compare the PS2 with the Accuphase PD-500.

So we changed the set up, the PS2 took the place of the Pioneer. CD album were again the two original USHER CDs. And it happened again, PS2 was playing better than the Accuphase, the same way it did with the Pioneer PD-S707. A new slap for my Hi-Fi face.

A few minutes passed with me at a stage of shock and Panos laughing. We had a small conversation whether I should write this post or not, we both jocked that the readers would easily classify us as Hi-Fi idiots of exceptional (Hi-End) quality. I said that I don't care, this is the true and this is what I am going to write. But still, something was not feeling right inside me.

Then it hit me again; at all the tests we did where the PS2 was sounding better, we were using the very same USHER CD albums. Could it be that every transport has some kind of preference at what CD media it reads and the PS2 loves this USHER CD, whereas the classic CD players hate it? Time to repeat the test by using our two original TELARC sample CD albums.

So we started again our usual blind testing. This time the Accuphase sounded slightly better than the PS2. Life was back to normal. Well, short of, but still, I felt a bit relieved.

At last, some conclusions!

Several days have passed and I was thinking about what conclusions we got from this test race.

First conclusion is that all the "classic" CD players we tested (Philips CDR 950, Pioneer PD-S507, Pioneer PD-S707, Accuphase PD-500) gave us the same exact sound when used as transports. It seems that there is such a thing like a good enough transport, above that point there is no sound difference. OK, the Pioneer Stable Platter Mechanism has proven it's value of immunity at vibrations, you have to knock the machine very hard in order to make it loose track.

Second conclusion is that the classic players and the DVD/BD-Rom based players (Playstation) can offer a different sound when used as transports.

The third conclusion is that it seems there is some kind of CD media and CD transport matching. We noted for example that the PS2 loved the USHER CD whereas when we used the TELARC CD, the Accuphase preferred it. Somehow, all our "classic" CD players shared similar preferences regarding the CD media. Now that I think of it, I have experienced mysterious incompatibilities between players and CD media; for example, a TDK CD-RXG 74 min written at my Philips CDR 950 will play everywhere (including discman, car CD stereos and notorious Aiwa all-in-one systems) except my Alesys ML-9600 recorder! This is an on/off case (meaning that the CD will not play at all) but I guess that there could be cases where a CD will play, but not in a perfect way.

Fourth conclusion is that a CD copy can potentially sound better at a certain CD transport than the original. That is because there can be a better CD media to CD transport matching with a copy. Regarding the certain CD copy I was using coming from my Alesys CD recorder, let me note that when you copy a CD at the Alesys Masterlink:

• The Alesys will read it at the optimum speed. If for example a CD is scratched, it will read it several times very slowly until it extracts all the data. I have managed to copy CDs that were unplayable to other players.
• All the data are recorded at the internal HDD.
• Then, from the internal HDD the data are recorded at the CD media. The recording process does not happen in real time, meaning that if for example there is a reading error the Alesys will take it's time to deal with it.

Fifth conclusion is that it seems there is not such a thing like a transport - DAC matching when using TosLink digital connection. I say this because all the 4 different CD players we used as transports had similar behavior - if there was a matching thing, I expect that we would sense it.

What I can still not explain is why when we played the CD copy and the original TELARC CD at the Pioneer and the Accuphase, we no longer were getting better sound from the copy like we did when we were comparing the PS2 and the Pioneer.

Still, the most useful conclusion is this: don't spend a fortune for a CD transport, just get a decent one and invest on the DAC, or even tweak it. Otherwise you will get nuts having several transports and using them according to which CD album you are playing!

The only alternative proposal I am thinking of is a CD transport that reads the CD faster and buffers the data, so there isn't any real time playback limitations in case the transport can not read correctly something; it can have a second chance and the buffer probably can help with the jitter.

Happy listening!

Chris

PS. You will probbably find the following post also interesting:
Back to the future: differences on sound quality of CD players.
CD Vs. computer audio, CD audio quality Vs. Hi-Res.