As an example, a 50,000 ohm cable into a 50,000 ohm input impedance at the amplifier would result in a 6 dB power or volume loss. The maximum allowable cable resistance and load input resistance must be limited so as to keep this high frequency roll off well above the audio band. With tube input circuits the input grid capacitance will probably be greater than the cable capacitance, due to the so-called Miller effect where interelectrode tube capacitance is amplified by the tube voltage gain. Because of this, cable resistance needs to be limited to approximately 35,000 ohms when the cable drives a tube amplifier or other tube unit. These tradeoffs have been worked out with the goal of optimizing overall performance with most systems.
Most systems have enough reserve gain to compensate for the resulting gain loss of one pair.
Due to the basic design, most of the cable length is of large diameter. Despite their bulk, the cables are flexible due to use of convoluted Teflon tubing. In the case of speaker cables, it is much more difficult to greatly reduce audio band skin effect because of the need to have high conductivity metal with large cross-sectional area for low total resistance. This low a resistance is needed for good bass control and extension due to the high drive currents and corresponding maximal cable voltage drops involved. It was found that this simple design requirement was by far the most important for the speaker cable.