Power cord and IC affecting sound..

[jneutron]

Decided to start a new thread...with a quote from mtry..

Great. Keep us updated. We are here to learn as well.

I detailed to Bruno in a jpeg, the mechanism surrounding how a PC cord and IC can affect the sound of a system. Also, how to isolate it and measure it.

The equation of the error voltage presented to the amp input is:

V_error=(I_p * f_p² * K₁ * K₂) / R_loop

V_error is the error voltage which appears at the amplifier input.
I_p is the current within the power cord, entire haversine spectra.
f_p is the frequency of the haversine harmonic considered.
K₁ is the coupling factor between the PC and the ground loop formed by the amp, source, and the power cords.
K₂ is the coupling factor between the ground path of the input, and the input signal.
R_loop is the total loop resistance formed by the pc ground, IC shield, and source ground.

As is evident by inspection, the error voltage is proportional to the square of the frequency component, the current of each harmonic in the line draw, the geometry of the PC/ground loop interaction, the geometry of the amp ans source internal grounding scheme, and inverse to the ground loop resistance.

So, clearly, a relationship between all the components is there...for me, that is not an issue..The real question is...given adequate test design and care, can it be reliably measured....and, once measured, is it of sufficient magnitude to affect the sound?

As is also evident from the picture, the mechanism I detail has absolutely nothing to do with the miles and miles of wire back to the power company..That argument is entirely without merit for the schematic I depict. (oh, forgot to label the top dot in the picture...that is the ground at the wall socket.

Also note...although I draw a hard ground for the source, it could be a simple capacitive coupling..one which provides sufficient signal path for the higher frequencies of the haversine..

What I did not include in this presentation is the bleed-back of high frequency audio signal into the line...the bulk parameters of the supply is insufficient to block the coupling.

Cheers, John