Found in 1948 MIT documentation, this 4-tube amplifier is characterized by its low noise level.
This circuit is used to cut the “click” in the loudspeaker of amplifiers when they are turned on....
April 2017 - The Shields of Seed Grove Modules for Intel Joule can now be obtained from Mouser...
RF or even switching transistors like the 2N2222 can be used in this circuit. The capacitors are ceramic...