Audio power amplifier utilizing multiple feedback loops

Claim 1

A POWER AMPLIFIER OF HIGH FIDELITY FOR DRIVING A SPEAKER THROUGH AN OUTPUT TRANSFORMER HAVING A SECONDARY FOR CONNECTING TO SAID SPEAKER, SAID AMPLIFIER INCLUDING SUCCESSIVELY CONNECTED TUBE STAGES COMPRISING A FIRST STAGE OF AMPLIFICATION, A SECOND STAGE OF AMPLIFICATION, A PHASE INVERTER THIRD STASGE, AND A PUSH-PULL OUTPUT STAGE CONNECTED TO SAID OUTPUT TRANSFORMER, SAID AMPLIFIER HAVING A MAIN FEEDBACK LOOP CONNECTED FROM THE SECONDARY OF SAID TRANSFORMER TO A CONTROL POINT WITHIN THE FIRST STAGE OF SUPPLY 40 DBS OF NEGATIVE FEED BACK, AND SAID AMPLIFIER INCLUDING STAGE INTER-CONNECTION MEANS MAINTAINING THE OVERALL LOW FREQUENCY PHASE SHIFT DUE TO ALL OF SAID STAGES WITHIN A RANGE THAT IS SUBSTANTIALLY SMALLER THAN THE LOW FREQUENCY PHASE SHIFT CONTRIBUTED BY SAID OUTPUT TRANSFORMER, MEANS PROVIDING A NEGATIVE FEEDBACK LOOP RESPONSIVE AT 5000 KC. AND ABOVE CONNECTING THE OUTPUT FROM ONE SECTION OF THE PUSH-PULL STAGE TO THE OUTPUT FROM THE SECOND STAGE, MEANS PROVIDING A NEGATIVE FEEDBACK LOOP RESPONSIVE AT 1000 KC. AND ABOVE CONNECTING THE OUTPUT FROM ANOTHER SECTION OF THE PUSH-PULL STAGE TO SAID MAIN FEEDBACK LOOP, AND MEANS PROVIDING A NEGATIVE FEEDBACK LOOP RESPONSIVE AT 20 KC. AND ABOVE CONNECTING THE OUTPUT FROM THE PHASE INVERTER STAGE TO A CONTROL POINT WITHIN THE SECOND STAGE.