DC self-biased vacuum tube differential amplifier with grid-to-cathode over-voltage protection

摘要

A single stage differential amplifier is disclosed as comprising a pair of vacuum tube triodes for amplifying two input signals and generating two output signals. The differential amplifier has DC self-biasing ability and grid-to-cathode over-voltage protection for directly coupling from the outputs of another differential amplifier. By possessing these unique features, this differential amplifier becomes an important building block in forming a balanced amplifier by cascading multi differential amplifiers in a directly coupled fashion.