power cables - not in the signal path?

Eh - sure the original post is oversimplification. Not doubting the other effects that are meant to improve the (former) AC signal, i neglect them in order to keep it easy to follow. All conversion, filtering and capacitive storage aside - the low-level signal does nothing more than opening and closing (I e modulating) the passage of a huge amount of electrons (obtained from the AC originally) through the device. It is not the low-level signal electrons that eventually get heard. if anything, it is the latter electrons that passed through the floodgate that eventually reach the audio transducer, etc.

I do stand corrected though regarding complexity - surely all amp designers make provisions to have a time-invariant pool (DC) to draw from. Maintaining such pool is hard though (is probably what separates boys from men).

No substance abuse here - sorry C.

Czarivey, I expect great philosophical insight from you on the topic. Please, do give it a stoned thought.

Czarivey - you said "proper offsets"? Please, do continue.

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.

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.

Czar - if that's what you were gonna say next... you probably stopped in time in the first place. My bad.

Geoffkait and Almarg - agree with both, with the small exception that attenuation of radiation takes place in any medium that is not vacuum to various degrees depending on medium and frequency (with the most striking example being metals - which are very effective in absorbing said radiation for practically all frequencies relevant here). The reason is (again grossly simplifying) that metals have those free carriers ready to move when they get pushed around by EM, so the EM energy reaching them is converted to electron motion.

The EM discussion touches on another topic (which I just realized). Kinda fun actually. Why do the "magic stones" work? (not that I have ever tried one, but I think I might).

The EM radiation at these frequencies is fairly delocalized - according to Heisenberg - hehe (the wavelengths can be on the order of yards to miles, compared to the wavelength of visible light which is on the order of fractions of micron). As such - any given quantum of radiation can be anywhere within that radius (with a certain probability). However, as soon as the wavefunction of said radiation overlaps with a strong absorber - there is a probability that it will get absorbed into it - and thus disappear for all other possible absorbers (such as unsuspecting cables lying around).

With that in mind - having such "magic stones" placed around the source of EM (but not too close so that their action as secondary emitters would not have least impact) would effectively suck RF from the environment.

Ha! If true then here goes the "magic stone" business out of business (now anyone can dump their spare iron and wrenches and such around their electronics and get crystal clear audio).

(incidentally - delocalization of wavefunction can be viewed as a reason for diminished RF influence with distance - the probability that the wave/quantum will be absorbed does decrease with distance - the more localized the wf, the quicker the probability that it will affect nearby cables diminishes).