sound detector amp/electret mike amp:

parts:

U1	LM741 op amp ic
R1	1 megohm resistor
R2, R3	6.8k ohm resistor
R4	1k ohm resistor
C1, C2	0.47uF ceramic capacitor
MIC1	electret condenser microphone

all resistors are 5 or 10 percent tolerance, 1/4-watt
all capacitors are 10 percent tolerance,
rated 35 volts or higher

this circuit amplifies the output of a regular electret condensor microphone quite nicely.. adjust sensitivity by turning R1