News

IsoTek Announces Sigmas One-Box Solution (17/7/2006)

The new IsoTek Sigmas was developed to bridge the gap between their statement products; Titan and Nova and the GII MiniSub, the end result being a one-box solution performing as closely as possible to a Titan and Nova combination.

As a starting point for the two high current sockets the Titan circuit was reduced by 50%. In the Titan development more and less stages of filtering were compared because with too many stages an overly dark sound is produced. Thus Titan is a 9-stage cascaded design using natural roll off and no "Chevishev" like characteristics, i.e. kink-less curves in the filter response. Following extensive listening tests the Sigmas circuit features 5 stages with additional delta filters at each end to emulate a full 9-stage design of the Titan.

IsoTek's Polaris X circuitry topology is used throughout the design to avoid cross contamination between components, this is combined with a refined version of the Nova's 'Adaptive Gating' circuit for the medium output outlets of the Sigmas. IsoTek pioneering design team have also created new and very unusual common mode chokes, being quite possibly the only ever company to consider the sound quality of these vital components. The aim was a sonic balance between a dark, low noise background and a clean extended sound with full top-end sparkle.

The Sigmas uses special MCB fuses which are far superior to conventional cartridge fuses, offering outstanding safety both physically and for the connected equipment (fast acting whilst allowing true transients).

The protection circuit uses highly specialised VDR devices that trip the fuse in the advent of over voltage. Many amplifiers, particularly class B power amplifiers, can sound poor if the mains supply is clamped at too low a level. The Sigmas' special VDR protection circuits not only allow these to draw enough voltage when necessary, but also ensure that they work at their best whilst still remaining safe. Another bonus of using these special VDRs is that they represent a high quality capacitor when idling thereby acting as a valuable shunt filter.

Finally the quality of components used is of the highest order, most components in an IsoTek product can be substituted by perfectly safe cheaper alternatives providing, in theory, identical filtering. Despite these components costing only 25% of those actually used, IsoTek insist upon only the highest quality parts to ensure optimum performance and reliability. For example, components such as RIFA paper capacitors, silver-plated 7N purity solid core copper wiring with FEP dielectric and silver ceramic Delta capacitors, all in order to attain the elusive balance of effective filtering and true high fidelity performance.

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