If the DAC is the same, how different do CD transports sound?

They should be very similar.   You've hit on a key point.  The main difference in the sound between CD players is the relatively cheap onboard DAC that each uses.  Eliminate the DAC and now you've eliminated most of the variance.

So it comes down to which CD transport drops the most bits and introduces the most jitter.   Good CD transports should do very little of either so it should be hard to tell them apart.

Jerry

@jasonbourne71 If you watch the video first, you won't need to say "Only a blind listening test to eliminate sighted bias and matched output voltage levels has any validity. Anything else is anecdotal!"

@audphile1

there’s a difference between CD transports. Higher end transports use better quality parts, better power supplies as well as better chassis and dampening. This results in improved sound quality.

That was my assumption going in. I think that was the assumption of Mr. Lovegrove. It was not borne out in this test. That’s interesting to me because it helps strengthens the argument for optimizing a CD-DAC combo by putting most of one's time, energy, and money into the DAC. This does not mean get a bad CD player. And this was a point I believe @jjss49 made on another thread, and now we have a video about this same topic.

The DAC will make the most difference. In my experience.
With a caveat…you must use a decent CDT…something like the units I mentioned above. Don’t waste money on a good dac if you plan to drive it with a $99 universal player from early 2000s. Just like anything else in this hobby, you can get by but to realize a full potential of any given component the rest of your system must be on the level. 
 

I posted this on another thread :

Transports are not all the same SQ wise and will either hold back or release the potential of the DAC. Benjamin Zwickel, Mojo Audio DACs, clued me into this when I was purchasing one of his ,and he was correct. I went from Cambridge CXC to Simaudio DT 260 and the SQ materially improved. Check out the threads on the top Project transport or the Jay’s transports and you will find similar experiences. Also, when you go beyond the likes of the Cambridge or Audio Lab transports one of the digital output connections might be optimized for SQ so you may want to have a DAC that accepts that connection. I initially used the SPDIF on the Simaudio and it sounded very good. However, out of curiosity I asked Simaudio if one of the connections was optimized for SQ and was told the AES/EBU was. The result was a further uptick in SQ. I believe the top of the line Project is optimized likewise, though folks using the SPDIF connection appear to be very pleased with its SQ. I don’t know if either of the Jay’s transports have an optimized output.

I'll further add, it's not about bling , expectation bias, status ranking, and the rest of the  commentary.  It's about the resulting SQ. Try them firsthand and decide for yourself .