Does the Transport make a significant difference?

Depends on the relationship between the transport and DAC. One thing I learned is the ability to slave the transport to the DAC so the DAC clock is the master reduces jitter more effectively than if the DAC is slaved to the transport where clocks have to be synchronized. This does assume that the DAC has a quality clock installed in it. In the latter scenario the cable is more of a factor because you have the clock signal and bits going through a single cable. My CEC/Lessloss combination separates these functions and uses the clock in the DAC as the master. This is similar to how some pro audio applications that I've heard in my system work as well with word clock inputs and outputs. Take a look at the Lessloss site to read more about this concept. They even give instructions on how you can slave a transport to a DAC.

Otherwise it's somewhat of a crap shoot as to whether a transport makes a difference. Some will, some won't, and in other scenarios a cable could have a bigger impact.

Shadorne, you are wrong in regards to your Jitter reduction theory, If the DAC is excellent at jitter rejection then it won't make a difference (one jitter immune input versus another should sound the same as it is all just bits). "

Doug,

If you re-read my statement then you will realize that I cannot be wrong. If a device rejects all incoming jitter entirely then there is no incoming jitter left (just the jitter from the clock in the device itself). Therefore a device which is said or demonstrated to be immune to jitter cannot possibly sound different with different amounts of jitter on the inputs - something else would need to cause the difference. A nasty ground loop on the Coax input creating circuit noise somewhere that is eliminated when using Toslink, for example. I am sure that many explanations can be imagined but it won't be interface jitter if said device is jitter immune and demonstrated to be so. It is simple logic really.

Douglas - I don't understand what Shadorne is wrong about -he says exactly same thing as you. Am I missing something?

Kijanki, he said, "If the DAC is excellent at jitter rejection then it won't make a difference (one jitter immune input versus another should sound the same as it is all just bits)." Seems to me the conclusion he reached is: the transport doesn't matter since jitter elimination will nullify any advantage of a higher end transport.

I don't agree with that. In my article I point out that a jitter eliminating DAC (the Benchmark) can help raise the performance of the poor transport, but it will not make it the sonic equivalent of the finer transport. There are still fundamental sonic differences. The distinction between them becomes even more profound in higher end rigs, even if the same jitter nullifying DAC is used.

I'm not trying to get into an argument over it; I just shared that I tested the premise and found it not to be true, at least not universally.

Douglas - I asked since I have DAC1 with cheap DVD player and no way to compare. From what I found on the Benchmark forum DAC1's jitter bandwidth is in order of few Hz and rejection is reaching 100dB at frequencies of interest (kHz). I know that sidebands, in spite of being at about -80dB with 3nsp-p jitter (taken from Stereophile article), are very audible since not harmonically related to root frequency but 100dB rejection on the top of it should be enough. Some Benchmark users reported audible changes between common transports while the others could not detect any change at all. In addition they could not find the difference between toslink and coax (other than ground loops that Shadorne mentioned) where toslink should be much worse jitter wise. Benchmark claims that there is absolutely no difference as long as player is "bit transparent" and not all of them are. Some, for instance, have digital volume control or another form of processing. Benchmark also tried thousands of feet of cat5 cable to prove that cable induced jitter is rejected and confirmed that difference is not audible. I wonder how much of the claim is Benchmark's marketing and how much of the user observed difference with expensive transports is a placebo effect. Using DVD player is convenient since they are cheap, play other formats and have good tracking, but I'm always interested in improvement.

At the level of transparency of the Benchmark many people complain that it is too clean up to point of being sterile. My first impression after switching from Cambridge gear (not much experience with high end) was that instruments must be missing on recordings I know well. It takes a while to get used to it (in positive sense).

Also - John Siau mentioned on the Benchmark forum that DAC1 was designed to avoid being warm because warm sound (even harmonics) does nasty job on the piano sound with its complex harmonic structure (but great for voice or guitar) making it sound almost out of tune. He claims that the only way to get real piano sound is to use headphones because crossover does similar thing. I don't think I would be able to hear it anyway.