Found in an American publication from 1947, this 4-tube amplifier has excellent sound quality. Its source makes use of a transformer.
This circuit makes use of a sensitive 5 mA reed-relay to be driven directly by a phototransistor. The...
This circuit was found in a 1967 RCA manual. The transistors are of the time. The adjustment is made to...
This powerful amplifier was part of commercial sound circuits from the 90s. The integrated circuit...