Power amplifier with clipping level control

An amplifier comprising:

• a first amplifier stage having an input, an output and a feedback circuit, said first amplifier having a first gain for producing a relatively low power output;
• a second amplifier stage having an input, an output and a feedback circuit, said second amplifier having a second gain for producing relatively high power output and having inherent clipping distortion at relatively high power output, the first gain and the second gain establishing an overall gain structure for the amplifier;
• limit means having a clipping level and being coupled between the output of the first amplifier stage and input of the second amplifier stage operative for limiting input voltage to the second amplifier stage above the clipping level of the limit means when the gain of the first amplifier stage is relatively high and when the gain of the second amplifier stage is relatively low;
• tube dynamics control means coupled to the feedback circuit of the first amplifier stage and to the feedback circuit of the second amplifier stage for simultaneously changing feedback impedance in the respective feedback circuits in opposite first and second directions while preserving the overall gain structure of the amplifier, said control means operative in the first direction for raising the gain of the first amplifier and rendering said limit means operative, and simultaneously reducing the gain of the second amplifier stage and reducing the output power thereof so that the overall gain structure is preserved;
• and operative in the second direction for increasing the gain of the second amplifier stage for allowing the introduction of the inherent clipping distortion, and for simultaneously lowering the gain of the first amplifier stage so that the overall gain structure is preserved.