This amplifier with gain control was obtained in a documentation from Signetics of the 80's. Transistors are of power and operational amplifiers are not common nowadays.
The time constant for this circuit found in a 1973 publication is given by R and C. The shot is...
Used with old projector films, this circuit found in Signalite documentation from the 1980s,...
This circuit generates damped sounds imitating a drum or other percussion instrument with...