All audio cables are adversely affected by the insulating material (‘dielectric’) in which they are sheathed to prevent short circuits. The best insulator of all for an audio cable is a vacuum, but of course this is impractical. Next best is air, followed by PTFE, polyester, polyethylene and then PVC, the most widely used cable covering. To reduce the influence of the dielectric to a bare minimum, Enhanced™ Isolda Deep Cryogenic Interconnect Cable uses a novel form of construction in which 3x0.1mm copper strip conductors are threaded through 3mm internal diameter PTFE tubing. Because the copper strip only touches the inside of the tube along its edges, the effective dielectric is about 95 per cent air, 5 per cent PTFE – a major improvement over conventional cable construction where the insulation is moulded around the conductor.

Two of these threaded tubes are laid side by side and then enclosed in a tough polyester braid to form the complete cable. Use of a flat strip conductor minimises series inductance, while the wide spacing of the conductors minimises shunt capacitance. So the cable imposes negligible filtering on the audio signal, whatever the output impedance of the signal source.

As a result of this thoughtful construction, Isolda Interconnect has a uniquely ‘hear through’ sound quality, devoid of the fuzziness, tonal imbalances and graininess which afflict other interconnect cables. But we’ve now found a way of making it even better.

As with the Enhanced™ Isolda Deep Cryogenic (EDCT) Loudspeaker Cable, the copper strip conductors are subject to deep cryogenic treatment and post-tempering prior to being assembled into the finished cable. 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.

Because the use of a shield may have a negative effect on sound quality, Isolda Interconnect is supplied unshielded as standard but with a ferrite sleeve at one end. In most hi-fi systems the source impedance will be low enough to prevent hum induction, and the ferrite (positioned at the ‘receive’ end of the cable) will be sufficient to suppress RFI. A shielded version is available for situations in which hum fields and/or RFI are an particularly severe problem. Where the source impedance is unusually high – which is sometimes the case with valve preamps and always the case with ‘passive’ preamps – use of the ferrite can cause a dulling of the sound. In this instance a smaller ferrite can be specified or no ferrite fitted at all.

A balanced version of the cable, terminated with XLR's, is available for balanced interconnections. Unbalanced cables are terminated with the highest quality collet grip phono plugs. These feature heavy gold-plated contact surfaces where ground contact is made most secure by way of the locking feature to ensure the lowest possible resistance in the ground line. Locking Din plugs are available for Naim. Enhanced™ Isolda Deep Cryogenic Interconnect Cable can be ordered in any length up to a maximum of 12 metres.
Listening tests to date have found DCT 300 unbeatable!

“The price may be high, but performance seems to justify it. Bass seemed the best in the group, in terms of both extension and control, and there is plenty of detail on offer. Treble and midrange are exceptionally clean, imaging is broad but detailed, and climaxes remain clear with full dynamics. Certainly one of the best interconnects around.” Hi Fi Choice November 2002.