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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's avatar
almarg
9,670 posts
 
06-10-14: Stevecham
EVERYTHING IS IN THE SIGNAL PATH
"Everything," so to speak, can AFFECT the signal path, to one degree or another. For example, turning on a dimmer switch in a different part of the house from the listening room can introduce sufficient distortion on the AC line to have audible consequences, in some situations. But I don't think that most of us would consider that dimmer switch to be "in the signal path," i.e., to be part of the path that is traveled by the audio signal.

Regards,
-- Al
cbozdog OP
63 posts
 
Geoffkait - no. EM radiation is produced when electrons move (and radiates away from the source that produced it). Such EM radiation decays rapidly with distance but can influence (make them move a bit) other charge carriers (electrons) nearby (for example, those in another cable). Such EM radiation is carried by photons with energies in the RF range, I think.
cbozdog OP
63 posts
 
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.
czarivey
5,946 posts
 
C, offset determines point of quiescent operation or stand-by or zero signal.
cbozdog OP
63 posts
 
Czar - if that's what you were gonna say next... you probably stopped in time in the first place. My bad.
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