| In this circuit, Q1 is a simple
amplifier that has its gain controlled by a variable emitter resistance supplied by FET
Q2. In the up position of S1, C3 discharges through R5 and the gain of Q1 decreases
because Q2 is driven toward cut-off. In the down position, Q2 conducts more, depending on
the setting of R6, which causes a gain increase. By varying R5 or C3, various fade rates
can be obtained. |