Kudos Sigao Drive

SIGAO DRIVE external crossover

SIGAO DRIVE represents a ground-breaking new approach to crossover design, never before seen in mainstream HiFi. Neither traditionally active nor truly passive -SIGAO DRIVE is an external crossover with no power supply, situated in front of the power amplifiers in the audio signal chain.

As long-time champions of active listening, Kudos endeavoured to find a better and more efficient route to the many benefits of active configuration, by removing every non-essential component from the reproduction process. This all starts with the power supply.Using new, high-quality components and a unique PCB design with custom mechanical isolation, Kudos has produced a new kind of crossover that features no power supply, yet remains technologically capable of sitting in front of the power amplifiers in the position of a conventional active crossover. The sonic result has been celebrated in its name-purity, accuracy, and stunning, ink black silence.

The Problem

Traditionally, a speaker’s crossover is connected between the power amplifier and the drive units, typically inside the loudspeaker enclosure, but occasionally mounted outside. The power amplifier cannot have complete control of the drive units because of the crossover components between them. What’s more, these components are likely to introduce some level of distortions and microphonic degradation.

To overcome this limitation, and in the pursuit of the highest resolution reproduction, several power amplifiers can be used -with each loudspeaker drive unit directly driven by a power amplifier channel.

The audio signal is then divided before the power amplifiers at signal level. This is accomplished using “active” filters using high quality signal level components and multiple transistor or op-amp circuits.However well designed, these circuits, and their required high-quality DC power supplies, add noise and distortions to the signal, reducing neutrality. These are especially obvious in an active system, due to its very high resolution.

The Solution

SIGAO DRIVE is an alternative method that had the Kudos designers go back to the design and engineering drawing board. Aided by Naim Audio’s erstwhile Technical Director, Roy George, who collaborated with the Kudos Audio team to help bring this in-house design to life, their response is an unpowered crossover that is connected between the preamp and the power amplifiers, again allowing the power amplifiers to grip and control the drive units by direct connection. Being unpowered, the Kudos crossover has no active electronics or power supply to add their inherent character to the sound, and thus the invasive components are eliminated.

Kudos used an enclosure with a carefully selected mass to control resonance, machined from a solid billet of aluminium. This helps shield the internal assemblies from external acoustic, mechanical and electrical disturbances. The PCB is decoupled from the enclosure using a purpose-designed PCB mechanical decoupling system. Compound dual isolation from residual vibrations provides the filter components with the best operating environment to maximise SIGAO DRIVE’s performance.