Abstract: A novel single-ended screen-regulated cathode-follower output topology for implementing vacuum-tube audio power amplifiers for the reproduction of high-fidelity music with minimal audible distortion. The screen regulation substantially reduces the distortions and noise in the current fed to the output tube by a non-regulated power supply. The noise and distortion of the power supply voltage are thereby prevented from intermodulating with and distorting the music signal.

Abstract: A novel single-ended screen-regulated cathode-follower output topology for implementing vacuum-tube audio power amplifiers for the reproduction of high-fidelity music with minimal audible distortion. The screen regulation substantially reduces the distortions and noise in the current fed to the output tube by a non-regulated power supply. The noise and distortion of the power supply voltage are thereby prevented from intermodulating with and distorting the music signal.

Abstract: A novel drive stage provides with low distortion a large amplitude signal, such as required for driving a cathode-follower output stage of a power amplifier. The drive stage comprises an amplification substage and a load substage. Each substage comprises two series connected vacuum tubes. Each substage is provided with a respective voltage divider network to provide that the two tubes of each substage share approximately equally both the quiescent static voltage and the dynamic voltage of the substage. The load substage coacts with the amplification substage to provide a novel mu-follower or SRPP circuit having approximately twice the voltage swing of a conventional circuit. This approximately quadruples the maximum power output of the cathode-follower amplifier.

Abstract: A cathode-follower power output stage is driven by a novel drive stage to provide with low distortion the large signal required to drive the output stage. The drive stage comprises two series connected vacuum tubes which share the large static and dynamic voltages of the drive stage so as to provide a drive signal having a large voltage swing, without generating audible distortion and without subjecting the drive stage tubes to excessively high voltages. The plate of a first drive tube is connected to the cathode of the second drive tube. A load impedance is connected from a B+ power supply terminal to the plate of the second drive tube. The grid of the second drive tube is driven by a signal responsive voltage divider network driven by the plate of the second drive tube.

Abstract: An amplifier for a capacitive load which includes a pair of high-voltage tube output circuits connected in a power output tube arrangement operating in push-pull for driving a capacitive load together with a feedback network connected between the Schmitt arrangement and a pair of transistors interconnected in a complementary difference amplifier circuit, the output of the complementary difference amplifier circuit connected to the driving tube of the power output tube arrangement to provide an amplifier output level having low distortion, positive DC centering and a high order of stability.