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about any DAC from your $250 receiver to your over the top $55,000 exotic hand made DAC are going to sound the same.
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Oh my... I will have to disagree with you on that... hehe
The differing available DACing methods (PLL, FIFO, Delta-Sigma, ladder, synchronous, asynchronous, etc) and qualities of DAC circuitry with regard to clocking and the newer asynchronous re-clocking, jitter time variance reduction, upsampling (asynchronous sample rate conversion), interpolation, oversampling, harmonic distortion (THD+N), etc, results in a huge disparity in sound qualities.
There are some exceptional DACs on the market for reasonable prices.
I always seem to hear about the
Benchmark DAC1 at a good pricepoint, but have no experience with it.
Personally, I simply don't feel that you can beat the analog output of a quality CD player if you have a proper analog bypass or dedicated analog stereo system. All the issues associated with external DAC systems can be reduced to a single problem - jitter. Jitter is a time based error that occurs between the clock we use to get the data off the disk in a CD transport and the clock used in the DAC system. In the simple CD player we use the identical master clock for these two functions and so in this 'synchronous system' jitter isn't a concern. The master clock that is in charge of getting the data off the disk is also used by the CD players internal DAC......
Jitter isn't really a problem that is determined by how accurate you pull the data from a disc. In a stand alone CD player you use the same clock to get the data off the disk as you do to clock the oversampler, the D to A converter and the sample and hold circuit, etc. Now indeed, this clock is divided and multiplied to obtain the correct rate, but the fact is this 'synchronous' system is nearly jitter free.
It doesn't matter how well you clock the data from the disc and assemble it into the correct format to transmit it out the SPDIF interface, you will have an embedded clock that must be re-created by various means to take care of the D to A process in another external circuit. Errors will be present in this re-created clock no matter what method is used unless you connect a second cable between the transport and DAC with the original clock. This would work beautifully, but correct me if I'm wrong, if you put all this in a single box, could we call it a CD player?
The player is the best possible situation, and in that regard, if the DAC and analog output circuitry of the player are well made (and there's the rub), then this situation will arguably beat the transport/DAC combo every time. You do require a good player though.
In the transport / DAC situation that exists when we use the digital output of a CD player, the responsibility for clocking the digital data from the CD player (whether PCM or AC-3 or DTS) is that of the SPDIF transmission format. The SPDIF format combines the data from the disk and the CD players clock using a method called biphase-mark encoding. The clock (in a conventional DAC) is then recovered by the sampling and DAC circuitry.
This recovered clock is then used to clock the DAC. Unfortunately, since the timing of the bits for DAC clocking is determined by the zero-crossing point of the signal, then any distortions can introduce jitter. It's a very real problem - not to be underestimated. No amount of buffering and reclocking will solve the problem that the recovered clock has jitter and is 'asynchronous' with respect to the transports master clock. There will always be some jitter irregardless of the jitter reducers used..
This time-base error is up for debate whether it's audible or not though. Can you hear the effects of jitter - maybe. Personally, I think so, and there's lots of anecdotal data to support it.
My suggestion is to get a good player and a good bypass or analog system.
brucek