Before evaluating whether an expensive cable is worth its price, it helps to understand what a cable is actually required to do — and what the laws of physics place beyond its capability regardless of cost.
A cable’s function is to transfer an electrical signal from one point to another with the minimum possible degradation. The parameters that determine how well it performs this function are resistance, capacitance, inductance, and shielding effectiveness. These are measurable quantities governed by the cable’s geometry, conductor material, dielectric material, and construction. They are not subjective. They can be placed on a test bench and evaluated precisely.
Resistance determines how much of the signal voltage is lost across the cable’s length. For an interconnect cable carrying a line-level signal between a preamplifier and power amplifier — typically a high-impedance source into a high-impedance load — resistance is almost never a practical concern. The signal levels involved are large enough that the voltage drop across even a modestly resistive cable is inaudible.
Capacitance matters more for interconnects, particularly when a high-output-impedance source is involved. High cable capacitance combined with a high source impedance forms a low-pass filter that rolls off high-frequency content. This is a real and measurable effect — and it is one that can be evaluated and specified without listening to the cable.
Inductance becomes significant primarily in speaker cables, where it can interact with the amplifier and speaker impedance at high frequencies. Again, this is measurable, calculable, and manageable with cables of reasonable quality and appropriate gauge.
The engineering requirements for a cable that performs these functions transparently are modest. They were understood and achievable decades before the high-end cable industry existed. What a cable cannot do — regardless of price, conductor purity, dielectric material, or geometric complexity — is add information to the signal that was not there before.