I have been tempted to QUANTITATIVELY (i.e. measurements and plots rather than “this sounds better” ) prove or disprove many things that are going on the audiophile market.
Mounting coils and magnetics carefully is good practice, so no quibbles there assuming you have the board space
. I have seen mains transformers mounted in old scopes such that they was directly under the CRT, in the null of magnetic field such not to cause any stray deflection of the beam.
Examples of things that irk me in the audio market:
* Mullard ECC83's with with different coloured writing fetch different prices due to their “differing sound characteristics”. I personally believe there is no difference between them, or some some of the reproduction valves which fetch much more sane prices.
* Point to point wiring over PCB's in audio amps. I severely doubt at audio frequencies there will be any real measurable benefit, assuming a decently designed PCB of course. I have worked on old point to point gear (HF transceivers, amps) and I really do not enjoy it.
* Super audio quality electrolytic caps – if you get the spec of capacitor you require does it matter if it says “Audio Quality” with some fancy logo on it? From a design perspective keeping a digital circuit quiet is a lot more challenging, yet we use everyday capacitors with everyday prices there with no problems (or I do anyway).
As an engineer, when I hear or read about audiophiles measuring things with their “golden ears” (without a double blind test) it infuriates me to be honest. I build an amp, guess what I do? I measure the THD and bode plot, (all you need is a scope, sig gen and some way of viewing the spectral content – spectrum analyser or FFT on your scope).
You can then measure a percentage improvement (if any), and see if those incredibly expensive coupling capacitors, HT caps, ECC83's with yellow writing, etc, was really worth their money.
end rant hehe