Anyone using a Blu-Ray player as a transport?

If you are talking about up-sampling of video to 1080p than it has absolutely nothing to do with CD playback.

Also, up-sampling of redbook CD will sound different but not necessary better. It depends on how it is done and your personal taste. It is like two cars of the same model, one with manual transmission, one with automatic. They will drive differently for sure but which one is better?

Sidssp, I am referring to the upsampling of the CD.
I wouldn't be using the Blu-Ray transport for video at all,
instead simply as a CD transport.
Why do you say that the upsampling of CD will not necessarily sound better?

Sidssp is correct.

Of the five or so DACs I've owned, I preferred the non-oversampling DACs because they sounded fuller, more natural and conveyed a larger sense of scale than the over-samplers. While upsampling resulted in more audible detail they sounded phoney to me. All except the tube DAC. Mind you, these were not expensive DACs either, and you may come away with an entirely different viewpoint.

In my line of work, it's kind of like a Photoshop file where someone went bonkers with the unsharpen mask. There's more detail, but it doesn't necessarily make for a better image.

Why do you want use a Bluray player simply as a CD transport? Makes no sense. Especially since you supposedly have a $12500 dedicated Wadia transport driving a $32K Boulder DAC? Please enlighten us.