Wherever electronic signals are transmitted by wire, be it telephone, video, digital data, radio or TV, the impedance (NOT resistance) of the interconnecting cable is ALWAYS matched to either the source or the load, to prevent distortion. In the case of hi-fi about the most important link of all is the speaker cable – and it is here that this rule is universally ignored. The result is a grossly mismatched connection, with the mismatch being typically twenty-to-one, as most speakers have a nominal impedance of about eight ohms and typical cables a characteristic impedance between 100 ohms and 400 ohms. No wonder speaker cables sound wrong!Townshend Audio Isolda Impedance Matched Loudspeaker Cable, which has a characteristic impedance of eight ohms, remedies this. To achieve an impedance match at such low impedance values the cable must exhibit very low inductance and high capacitance. It is well known that high capacitance can upset some amplifiers, which become unstable. To counteract this, a correctly engineered, inaudible inductor, in parallel with a damping resistor, is inserted in series with each leg of the cable, at the amplifier end, for assured stability. The two inductors also act as a filter to prevent radio frequency interference (RFI), present in abundance at the end of the cable, from passing to the circuitry of the amplifier. Further, the very close spacing of the conductors in the cable provides a further level of RF rejection. The result is black silence. What happens when the impedance between the cable and the speaker is closely matched? The answer, MAGIC! The sound is fast but not bright; it is clear, open, fatigue-free and grain-free. Bass notes are precisely defined, deep and tuneful, with amazing impact. The midband, especially female vocals and solo instruments, takes on a naturalness never before heard from reproduced sound. The treble is smooth and fast with both brilliance and sparkle. But the cables never sound bright, brittle, grainy or spitty. They just sound ‘right’. These inherent Isolda characteristics are further enhanced by subjecting the copper conductors to deep cryogenic treatment (EDCT). The copper is slowly cooled to about –190 degrees Celsius, held there for a number of hours, and then gradually returned to room temperature. EDCT is proven to improve the lattice structure of copper, eliminating small ‘dislocations’, and has an amazing effect on the cable’s final sound. Dynamics are improved, clarity is further enhanced and the sound takes on a difficult to describe but immediately recognisable naturalness that untreated cables cannot match. Construction of the Isolda Loudspeaker Cable is both attractive and practical. The two flat strip conductors and their very thin tough polyester insulation are sheathed in a hard-wearing polyester braid, terminated at each end with non-magnetic stainless steel cylinders. These enclose the complex cable transition as well as the inductors at the amplifier end. Flexible, insulated copper wire tails connect to banana, spade, BFA or Speakon connectors to complete the cable. The strip conductors are arranged to slide over each other, through the braid and through the cylinders, to minimise buckling when coiling the cable. It can be laid under carpet and folded at right angles. It must not, however, be trodden upon when on a hard floor or when on edge. Isolda Loudspeaker Cable is sold in pre-terminated lengths. As the cables are impedance matched, which means that the sound does not change with length therefore unequal runs may be used for each speaker Bi- or tri-wiring makes a significant improvement.
Biwiring is implemented by parallel connecting two identical cables. The parallel connections at the amplifier end is by unique “piggy back†banana connectors.
These cables get rave reviews in Europe and are true audio bargains as in Giant killers, this is a 2 meter pair.
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