The powerplant that's where the source of all mains power is... and I do not mean the one from Paul McClown.
Have you ever wondered what power would be best suited ?
Hydro power (for that liquid sound)
Wind power (for that extra bit of air)
Solar Power (for the ultimate brightness)
Coal Power (for a blacker background)
Natural Gas power (for a more natural sound)
Oil powered (for that smooth sound)
It's not just the last meter(s) that matter but the source is.
But if the audiophiles and audiophools are right ... everything matters.