A typical MOS-FET push-pull power output stage consists of both positive and negative polarized transistors. However because it is impossible to make two identically behaving transistors with opposite polarization, small differences in the electrical characteristics must be accepted. This compromise of imperfection will create an asymmetrical amplification with a different signature in the positive and in the negative signal response. This often results in audible distortion and listening fatigue.
The Gato Audio TwinFET technology features only two but identical and perfectly matched transistors with same polarizing in a push pull coupling. By our special driver stages, we have created a circuit that compensates a negative polarized transistor to deal with a positive signal. This special circuit enables us to use two identical negative polarized output transistors instead of a pair of "complementing" positive and negative polarized transistors in the push-pull coupling.
The TwinFET technology offers a perfectly symmetrical sine wave reproduction and uncompromised natural audio performance.
Compared with the reference sine wave, the TwinFET offers a symmetrical response. Both positive and negative parts of the waves are perfectly identical.
The typical push-pull circuit (blue line) is, with its complimenting positive and negative transistors, returning an asymmetrical sine wave response.
It is crucial for any high end power amplifier to be able to deliver high voltage and strong current instantly and in any load. This calls for fast components that can deal with both high current and high voltages. The typical compromised solution is to use several paralleled output devices. Each transistor might be fast and capable of working with high voltages, but only in groups also capable of delivering high current. However; this leaves the delicate audio signal a group of paralleled transistors. In this "choir" of more or less identical transistors, all of them are "singing" with a slightly different voice than its brothers and sisters. Not only is this smearing the tiny transients and the time domain, it is also stressing the components as they constantly need to either hold back the neighbor transistor or help it to push forward – never just follow along in the pace and rhythm of the music.
The multiple transistor circuits may off er great power handling but returns an asymmetrical and smearing of the time domain.
To solve the problem of the "bad choir", we went outside the typical audio industry specified components and suppliers. We found a real tough professional MOS-FET designed for high current switching in electric cars. One single MOS-FET of this kind, can handle up to 500amps or what is more than five typical high power transistors combined can do. It will deal with both extreme voltages and extreme current, without the need of multiple brothers and sisters to carry the load.
The simplicity of the TwinFET technology off ers perfect time domain symmetry and clean and clear sonic performance.
The Gato Audio TwinFET amplifier is named from the design with two perfectly identical transistors that ensure perfect sonic timing, almost unlimited power and a perfect symmetrical high voltage swing. The TwinFET technology is sonically far superior to designs typically only focused on delivering voltage and current – not a perfect symmetrical time domain.