Worlds best DAC

I'm not sure digitsl transports I've been exposed to qualify as SOTA.

In my system, I've heard:
-- Ayre cx-7e
-- Oppo bd95
-- marantz sa8004

In other systems, at dealer showrooms and friends, cd and sacd transports from:
-- Cary Audio
-- Oppo
-- bel canto
-- esoteric
-- ayre
-- sim audio
-- Electrocompaniet
-- modwright Sony
Others I can't remember. I don't think any have been super high end components though, maybe more mid tier, but many solid contenders, and some in systems with much higher end gear than my modest setup.

My favorites of what I have heard have been the ayre, the esoteric, and the marantz.

I'd take the transporter and computer files over any of them. If I had to boil the difference down to one concept, it is that with computer audio, the transport seems to disappear to me, while spinning transports seem to add a color of their own, they seem somehow more present. A really subtle and very hard to articulate difference. Not to mention the massive convenience factor of 20000 songs at my fingertips, literally (iPad).

I think it may not be an entirely fair comparison though because I've essentially tuned my system around the transporter, keeping components that have synergized well and moving on when not.

I should add that if anyone wants to swing by with a $20k transport I'm up for the comparison! (Tampa Fl area).

Oh yeah, another one that stood out to me was a MacBook pro feeding an ayre qb-9. That sounded incredibly good. Might actually be my favorite front end after mine. Of course, that's also computer files.

I really want to stress that I am by no means an audiophile expert, just another amateur listening to as many things as I can conveniently come across. And as I've said the circles I run in don't include front ends costing upwards of 10, 20k, etc.

So, all in context.

I think we are too hung up on the merits of "computer files" versus "CDs". They are both the exact same data. What matters are the timing errors in the transfer of this data to the DAC. In typical synchronous transfer mode, the transport provides the clock to the DAC, so it stands to reason that whatever transport provides the most accurate clocking sounds the best. You can get USB converters with very good clocks - better than what you find in any CD transport. This is why with the top notch hardware computer audio typically beats CD.

what might be worth doing is to compare a "hi rez" file or disc , with the redbook version.

i have done this, as i own, several reference recording cds and hi rez discs.

i found that one is different but not better than the other.

i have also been thinking about the quest for the world's best.... (fill in the component).

it should be obvious, that since audio is a subjective subject, there will always be differences in opinion as to one component being better than another.