@ TJ-Sully & CanadianMaestro
The question of CD transports is a complicated one.
It is not a mtter of simple extraction of 0s and 1s from the disc. Japanese manufacturers have discovered problems inherent to digital equipment long before CD was even invented. Later they also discovered new techniques to combat these problems.
A well-designed CD transport should have a stable CD drive void of vibration, mechanical components that are inert enough to be immune to vibration, laser assemblies with precise servo mechanisms, stable power supply to these servos (even grounded in some cases) etc. Some Japanese manufacturers were not happy with what was available so they made their own drives. Companies like Sony, Kenwood and Pioneer.
All of these things are expensive to make, a lot more expensive than installing a reference-level master clock which is the best you can get with a modern-day CD transport.
A few years ago, I did extensive tests on different CD transports. The results were interesting to say the least. The best-sounding and best-measuring CD transport was in fact DVD player from Pioneer. Nothing special, a cheap player bought only to do this test and compare it against a dedicated CD transport that costs literally eighty (yes, 80) times more.
No service manual for the Pioneer made it impossible to discover why this is but then I saw something about "Perfect Playability" feature. According to Pioneer, all of their machines, at least of this generation, can play all discs, no matter how badly damaged. Needless to say, all of my discs are in perfect condition, but this means there is some kind of processing inside that deconstructs, interpolates and then reconstructs the original dana. Obviously, this has to include audio syncing as well. Now of course, this system was designed for video primarily but obviously, it affects audio as well because the square-wave on the oscilloscope was essentially textbook-like. Only the slightest artifacts are visible at maximum magnification.
But no matter how good the transport is, errors can still creep in once the signal leaves the S/PDIF generator within the CD transport. If the input receiver chip inside the DAC has nothing to combat this, this will only get worse when it reaches the actual D-A conversion. In fact, I'd say that the quality of the input receiver chip is probably more critical than the entire CD transport.
The Pioneer DVD is as good of a CD transport as I have heard and I already have a Bryston BDP-2 with the BUC-bord installed.
In all fairness and interest of full disclosure, our tests were inspired by Lampizator website, their Pioneer DVD player modification page in particular.
As for modern-day CD transports, they are pretty much gone. Unless you want to spend a fortune which is something I wouldn't do myself, even if I had the Money. It appears to me the best one comes from Onkyo, namely the C-7000R. It belongs to their top-level range and has some interesting features. It is a CD player in fact but all analogue circuitry can be switched off leaving only the digital outputs active. It has a balanced AES/EBU output and thermally-stable clock. More importantly, the clock feeds the digital outputs directly with a shielded wire thus bypassing the circuit board completely.
For what it's Worth.
Cheers!
Antun
