About 3 months ago I had two (my amps and sources are about 20 feet apart) dedicated 20 amp circuits installed into my audio/media room. It did make a very noticeable improvement in reduced noise and distortion that comes through as much clearer imaging and soundstage. For my system goals, I am trying to get live music to be more three dimensional and lifelike, and for that objective, this was one of the most significant upgrades that I have done.
I spec'd to the electrician to use 10AWG wiring, and Synergistic Blue outlets, which similar to OP also made him laugh. At that time he told me that was total overkill, but he was happy to do the work if I wanted. When the work was done, I had him listen to the difference with a simplistic A/B of moving power cables from a single shared 15A circuit to the two dedicated circuits, and he could clearly hear the difference. What stood out to him most was that music sounded noticeably more realistic through the new 20A circuits.
For my system and home environment, this made a very large improvement, and it was one of the best ~$2,000 investments I have made. I had a lot of AC noise issues with other devices on that shared 15A circuit, and separating my analog audio made a big difference. If I had done just one 15A dedicated circuit, I think it would have done just as much improvement though. I believe that the main benefit has come from not having my analog two channel gear sharing a single circuit with two Mac mini's, a NAS server, and some other digital devices with noisy SMPS's. It may not make as much improvement for others, but for me this has been a great upgrade...
