why do power cords make a difference with transpor

I have been playing around with my Marantz SA-14. It is a great stand alone player that is made even better by a Shunyata Python. Recently I used the SA-14 as a transport with an Electrocompaniet dac. It would seem that the dac would benefit most from a better power cord because it decodes the 1's and 0's. The transport just turns the disc. However, the Python sounded much better on the transport than the dac. More bass, much better separation between instruments, and clearer overall. Why? Surprised? I am not at all technical but I would appreciate any thought you would have. Thanks