I have found out why new cables and tweaks actually work!

@lanx003   Afraid you're wayyyy too far gone for me.

But I think you mean 'conductive'.  Now, you say 'the dust layer on the cables becomes conductive"  But the cables are heavily insulated.  So the thin film cannot transmit any signal into the dielectrics.  Dust can land on the terminations, so true believers might clean them often.  It occurs to me that taping the terminations with insulating tape or some other benign tape will prevent dust from landng on them and save you having to clean all the terminations before sitting down to listen.

If you have amplifiers with ventilation holes on the top surface, have you ever looked to see the amount of dust accumulated on the circuit boards and components inside.  Crikey, it's thick and sitting on the actual boards that carry....oh no!!...signal.  Your music.  Anyhow don't worry!  It's really hot in there, so any humidity that might tend to make the dust conductive soon evaporates.  Phew!  A narrow escape.  Still it doesn't do any harm to go in there from time to time and vacuum out the dust...very carefully.  The fastidious will want to polish the surface of the circuits on the board.

IMO you should never perform such an undertaking unless you are a qualified tech in the filed of cleaning fluids, and have a degree in this.

I used to work for the DoD making cleaning fluids for submarines to make them extra stealthy. The secret is dolphin spit. Turns out their spit causes a hydrophobic electrical charge to build on their noses which repels water and makes it easier for them to glide through the water.

Trouble is, we can only gather it while they sleep.

@erik_squires    On cables I think I mainly agree with you.  I am not so pig headed as to think cables carrying signal cannot make a difference.  But a far smaller difference than changing an amp, or cartridge, digital player or speakers.  And even smaller when evaluated on a per dollar basis.

But passive stuff like power cables and fuses and raising your wires on little pyramids cannot make a difference, whatever some people convince themselves they are hearing.

@clearthinker  After decades of listening, and hearing how audiophiles and non-audiophiles perceive sound I have my own theory which I do not need others to ascribe to:

• Amps and speakers are more sensitive to cable impedance than we normally think but not by a lot.

Yes.  They are sensitive to interconnect and speaker cable impedence, but not that of power cables.  Or indeed fuses.  So long as they can pass the necessary current.

But, on a higher philosophical plane, how sensitive do we normally think they are?