OK Red, probably nothing will satisfy you, but I will try; my version of Obama's birth certificate.
In a conventional RC power supply the output impedance is about 800 ohms or thereabouts.
In a more sophisticated shunt zener regulated supply, that output impedance drops to about 10 ohms.
In an active regulated power supply, properly designed, the output impedance can be less than 1 ohm.
When the active device that the supply is powering draws current, it causes a voltage drop across the supply output. The larger the output impedance of the power supply, the greater the voltage drop. This actually is imparting a small version of the audio signal at an unintended place in the circuit. If more that one active node is supplied by a common supply then the unintended signal is mixed and sent to all nodes. There is name for this - - - distortion. The level of the mixed audio signal floating around on all the common supply nodes is very very small. We can't actually measure it on our test equipment. However, it is really really easy to evaluate and hear when you build two identical audio circuits, one with a conventional RC supply, the other with multiple very low output impedance regulated supplies. One regulated supply is good, one per channel better, one per tube better yet, or, as we have done, one low impedance regulated power supply for each plate of each tube used in the unit.
This sir, is what nobody else had done that we know of. Sorry, giant wonder caps don't help, their output impedance is determined by their nature, not whatever purple prose has been used to sell them at grossly inflated prices to suckers.
Regards,
Frank Van Alstine
