Technology

Truly-Constant Voltage Mode

Certon power amplifiers employ a proprietary technology for quiescent current control. It is called Truly-Constant Voltage Mode (TCVM). The result is a high damping factor, which is generally acknowledged to provide for more accurate sonics such as a more assertive bass reproduction and improved musical resolution.

A loudspeaker is a continuously varying load when music is being played, i.e. its impedance is not constant but changes along with the music. This causes the output voltage of an amplifier with low damping factor to sag. An amplifier that has a high damping factor on the other hand has an output voltage that is stiff. It remains substantially unaffected by fluctuating loudspeaker impedance, i.e. it is substantially load-invariant. Such an amplifier is therefore said to operate in constant voltage mode.

Certon amplifiers thus operate in constant voltage mode. Because of exceptionally high damping factors of Certon amplifiers, Certon calls this technology "Truly-Constant Voltage Mode"

Certon amplifiers accomplish a high damping factor without excessive feedback, which assures excellent stability and overall performance.

The schematic to the right is a simplified outline of a general audio amplifier, connected to a loudspeaker. The amplifier has differential inputs, one of which constitutes the audio input, and the other of which constitutes a feedback input from the output of the amplifier. The amplifier has an output impedance (ZOUT) due to so-called degenerative local feedback in the output power stage of the amplifier. The output impedance and the loudspeaker make up a filter that has a phase error which thus is fed back to the input. In severe cases, the amplifier becomes unstable and produces distortion.

The schematic to the right is a simplified outline of Certon's TCVM technology. The red X indicates absence of output impedance, which is due to elimination of local feedback in the output power stage. Accordingly, the phase error is effectively eliminated.

As a result of the elimination of degenerative local feedback, there is an exceptional improvement in damping factor, which can be seen in the diagram to the right. The diagram shows the damping factor as a function of frequency for Certon Mark 1. At 1 kHz, the damping factor exceeds 1500.