power cables - not in the signal path?


According to popular wisdom the AC power is not in the signal path and therefore a power cord, AC conditioner or similar should have zero audible effect.

In a don quixotesque attempt I'd like to turn this perception around: the AC is 100% in the signal path - more so that the actual low-level signal that gets amplified, and I think I found the simple words to clarify this.

The low-level signal is actually only modulating the high-voltage (high-intensity) signal produced by the transformer. Those electrons from the transformer are the actual electrons we "hear". The low-level signal is simply lost in translation. In a simple example, a 0.1V peak-to-peak sine signal gets amplified (say) 10x by a 10 V continuous (transformed) DC. The output is (say) a 1V sinusoid oscillating back and forth in time. If the 10V continuous is NOT actually exactly 10V (but is actually has noise) - then the noise will directly reappear "riding" on the 1V output.

Hence the need to keep the AC noise-free.

(Of course I purposefully neglected for simplicity the other effects (need for instantaneous delivery of power, etc..) for which I did not find a simple enough description (without reference to I/V curves and impedance / capacitance details, that is).

Does is make sense?

Thanks
C.
cbozdog
Almarg - sure, the signal path is that which carries the information. Nothing is in the signal path until it is. The signal changes many hands (digital, analog, sometimes back and forth) - each time is actually physically converted into something else. In that sense, even amplification is a conversion (to a higher-intensity signal). For the purpose of this example, is might be viewed as taking clay from a jar (AC, or a rectified version thereof) and molding a faithful reproduction (or encryption) of the original.

Blah, this came out too poetic - sorry.
C, offset determines point of quiescent operation or stand-by or zero signal.
Czar - if that's what you were gonna say next... you probably stopped in time in the first place. My bad.
Cbozdog, thanks for the response. I suspect we are pretty close, I am pretty sure ALL electromagnetic waves are actually photons, including Gamma Rays, RF, x-rays, and music signals. RF waves! to take an example do not attenuate much over distance, traveling at the speed of light or close to it.
06-11-14: Cbozdog
... EM radiation decays rapidly with distance...

06-11-14: Geoffkait
RF waves! to take an example do not attenuate much over distance, traveling at the speed of light or close to it.
You're both right, sort of. I believe that the main reason RF attenuates as distance increases is that it "spreads out," and therefore while the total amount of energy that is present at a given distance does not decrease a great deal as distance increases (assuming propagation through a medium that is conductive to it, such as air or a vacuum), the amount of energy reaching a given cross-sectional area at which it may be received will decrease considerably as distance increases.

The degree to which that happens will of course vary greatly depending on the directionality of how the energy is launched, e.g., omni-directionally, or as a beam that is focused with some particular degree of sharpness.

Regards,
-- Al