Does a new cd transport require break-in time?

Burn in is just one of these myths. For speakers a few hours may be all that is needed, but speakers are mechanical components. In the case of electronics there is no theory that could explain why they would need break in.
If you want to test the hypothesis, comparing a product over the course of many hours is an invalid methodology, of course, because given humans’ short audio memory you cannot do a direct comparison over time, and time travel is yet to be invented. So what you would need to do is a double blind level matched comparison between a used item and one that is still in virgin state. Guess what?
In the case of a disc transport, it is my considered view that there are no sonic differences between them anyway. Their output is bitperfect and bitperfect is bitperfect. Anyone who wants to argue that they do have a sonic difference should show that bit by bit the files are actually not the same.
And that, of course, is the beauty of the digital revolution. Bits are bits, and that is good news, because the numbers in our bank accounts do not suddenly change because the bank uses a new hard drive that still has to be burned in.

willemj

... comparing a product over the course of many hours is an invalid methodology, of course, because given humans’ short audio memory you cannot do a direct comparison over time, and time travel is yet to be invented. So what you would need to do is a double blind level matched comparison ...

Sorry, but you don't know what you're talking about. You can't logically on the one hand insist on a double blind level matched evaluation, and then deny a listener the opportunity to listen at his leisure. Either your testing methodology is capable of producing a valid result independent of listener bias and other testing errors, or it isn't. Your position sounds like you have no faith in the testing protocol you so tirelessly promote here. Perhaps you should search for a test in which you can place more confidence.

Huh??

Oh, no, not again! The dreaded Double Blind Test raises its ugly head! 👹 The threat of double blind testing has done a great deal of harm to the hobby by preventing progress and suppressing innovation and creativity. Double Blind Testing is the favorite weapon of died in the wool pseudo skeptics and knuckle dragging naysayers, as if they automatically win any argument by declaring, "But it can’t pass a double blind test!" Ironically, the knuckledraggers never actually do double blind testing themselves. That’s for someone else to do. In fact the naysayers don't even know how to conduct a proper double blind test.

Anything that changes the risetimes and falltimes of the output of the transport (i.e., the amount of time it takes the signal to change between its two voltage states), or that changes the amplitude or spectral characteristics of electrical noise that is riding on that signal, or that affects distortion of the signal waveform that will inevitably be present to at least a small degree, could conceivably end up affecting timing jitter at the point of D/A conversion in the separate DAC component. The degree of any such effects, if present at all, would certainly depend on the specific designs of the two components, and perhaps also on how they are interconnected and on how AC power is distributed to them (which in turn can affect ground loop-related noise).

But is it possible that breakin of the electrical and/or mechanical components in a transport could affect these characteristics of the output signal to an audibly significant degree? I don’t think any of us can answer that definitively, but I also don’t think the possibility can be categorically ruled out. On the other hand, though, it certainly seems possible, and in fact likely, that **some** reported findings of breakin phenomena are due to unrelated changes in the system (such as ongoing aging or breakin of other components), or in its environment (such as changes in AC line voltage or noise characteristics, or in ambient temperature). Not to mention the possibility of inaccurate recollection.

Personally, I don’t use a separate transport so I can’t speak from experience. And in any event I would by no means extrapolate experience with a particular transport/DAC combination to other designs and other systems. But given the foregoing my expectation is that the truth lies somewhere in the middle ground between the opposing points of view that tend to be expressed on such matters. In other words, IMO the answer to the original question is a definite "maybe." :-)

JMHO. Regards,
-- Al