Tech Talk - June 2008
| May, 2008
Cable capacitance, measured in picofarads per foot (pf/ft), describes a cable’s ability to store an electrical charge. It is a byproduct of an instrument cable’s constituent parts: the thickness of the insulation, the insulator’s dielectric constant (a measure of a material’s conductivity), and the diameter and composition of the conductor.
As a bass’s signal travels through a cable, the interaction between the conductor and the shield creates capacitance, allowing a small current to flow across the insulation and between the two conducting elements. Coupled with a high-impedance signal source (like a passive bass), the capacitance turns the cable into a kind of lowpass filter, cutting high frequencies in direct proportion to capacitance and cable length. An active bass, with its buffered low-impedance output, isolates the instrument from this capacitive effect. In essence, a cable with low capacitance is more transparent-sounding than a high-capacitance cable. The Elixir Cables’ 10 pf/ft capacitance is extremely low for an instrument cable; most average around 30 pf/ft.
