I have a highly modded Arcam alpha 5 NOS, and Philips 963sa with a dimming display. These are directly connected to tube mono amps and dynaudios. I believe that I can hear the difference in strategically changed resistors. There is only two caps in the signal path and changes here are easily discernible. I can't detect the display on/off difference in the Arcam, nor the video off circuit switch on the Philips! So much for my golden ears, but I still use the features and enjoy the music!!!
For crying out loud
If you have the option, and you haven't done so, try turning off the display's on your digital gear. I know that I tried this years ago and, discerning no difference, concluded that this was just one of those anal audio things. Well, my system has evolved since then and I accidentally turned off the display on my Modwright Sony. I am now realizing improved definition and detail, voices are more natural, instruments have a more realistic timbre, images are better defined, and everything emerges from a blacker background. I really feel like a nincompoop. Here I am rolling tubes, shifting footers and stuff, and all along, a significant improvement was a push of the button away.