Does transport matter if using external DAC?

No question about it, makes a big difference, my CEC took things to a whole new dimension. Also, the choice of digital cable will play a part in this as well.

Rock Virgo has explained things well; it ain't just an issue of ones and zeros.
Also, if you scroll down just a bit on this Digital Forum, you'll find threads with people asking about which transports are best. There's an obvious inference you can draw from that, plus info for you in the threads too.

A great bunch of answers, a pleasure to learn from.

I've owned four one-box players, two transports and two DACs, and I've used one of the players as a transport. My most recent DAC was a clear step up, first with a player as transport, then with a pure transport once I had sold the player. The final configuration was much the best, I thought. In other words, the transport made a great difference, in speed, articulation and soundstage, in this case.

Digital cables also make a great difference, but if you limit yourself to considering ones and zeros then cables are voodoo too.

If differences can be perceived, but they don't show up on instruments, then we haven't learned what or how to measure yet. Just yesterday I read on Richard Sequerra's site a wonderfully lucid explanation of why and how "inaudible" frequencies, by intermodulation, affect what we hear.

Hi all.....not to go with the crowd, but the crowd is absolutely correct. In my experience, moving to a CEC transport for me changed everything. You have to hear it to believe it. Transports REALLY matter.

In my experience, the transport usually matters MORE than the DAC.