Taken from the tact s2150 owners manual:
The digital input is taken to the central processor where it is reformatted into apulse width modulated signal of extreme precision. The pulse rate is measured atprecisely 384,000 pulses per second. Each pulse can have 256 different widths,with the narrowest pulse being a mere 10 nanoseconds wide. The clock frequencytherefore is 98 MHz. The central processor uses proprietary patented algorithms(Equibit) to arrive at exactly the right combination of pulse widths produce a highlyaccurate waveform. This is the most fundamental departure from conventional am-plifiers. TacT defines the waveform mathematically - we are not trying to follow oremulate a waveform by using feedback or feed-forward.Once the decision of the duration of the pulse is made the central processor con-trols FET-switches at the output with extreme precision. Voltage and current aredrawn from the power supply and fed to the speakers.The level of playback is controlled by adjusting the voltage of the power supply. Asthis voltage is switched directly to the speakers, it is of paramount importance thatthe power supply be totally free of ripple and noise. For TacT digital amplifiers, aswitch mode power supply of extreme precision with ripple rejection of more than135 dB has been developed. At full volume (voltage) the TacT M/S2150 delivers 58volts, equivalent to 150 Watts into 8 ohms. To reduce the volume the voltage of thepower supply is reduced. This means that the volume control is no longer part of anactive circuit.
