Power amplifiers coupled in series

A high voltage audio amplification method comprising

• providing an audio processor comprising an audio input and a control output and a first power supply having at least a positive DC rail;
• arranging the audio processor and the first power supply with a common ground potential;
• providing a second power supply having at least a positive DC rail;
• arranging the second power supply with a floating ground potential;
• providing a first amplifier full bridge and connecting it to the first power supply and the control output of the audio processor;
• providing a second amplifier full bridge and connecting it to the second power supply;
• providing an isolation barrier and establishing a connection between the control output of the audio processor and the second amplifier full bridge through said isolation barrier;
• arranging an amplifier interconnection between an amplifier interconnection output of said first amplifier and an amplifier interconnection output of said second amplifier;
• coupling a load between an amplifier output of said first amplifier and an amplifier output of said second amplifier;
• providing at said audio input of said audio processor an audio signal to be amplified to high voltage.

A public address system comprising

• a power amplifier system comprising
• an audio processor comprising an audio input and a control output;
• a first amplifier full bridge connected to a first power supply;
• and
• a second amplifier full bridge connected to a second power supply;
• wherein an amplifier interconnection output of said first amplifier is connected to an amplifier interconnection output of said second amplifier;
• wherein said first amplifier and said second amplifier each comprises an amplifier output for a load to be connected in between;
• wherein said first power supply and said audio processor has a common ground potential and said first amplifier is connected to said control output;
• wherein said second power supply is floating with respect to said common ground potential and said second amplifier is connected to said control output through an isolation barrier;
• and wherein said public address system further comprises an audio source input connected to said audio input and two or more loudspeakers coupled to said amplifier outputs in parallel connection with each other.