Muratc,
Interesting. Thanks for sharing this. Intuitively I would have guessed the opposite. I would have thought that the transport, being an all digital device with optical digital output, would be very robust with respect to power supply condition...being digital either it works or doesn't. The DAC, on the other hand, being an analog device, might convey power supply condition to the output signal in some manner.
Thanks for sharing and happy listening with your awesome gear!