The tremolo effect circuit widely used, making noise in the electronic music scene. The height of the modulation signal by low frequency between 1 Hz to 10 Hz. This result will sound good, When frequency be modulated in sine.
Figure 1 Tremolo Effect Circuit using uA741
The circuit as Figure 1. Music signal is buffered with emitter circuit of T1. And so, entered IC1. Which adjusted growth rate by P1. The output of IC1 enter into a modulated diode D1 / D2. The output of buffer by the emitter as T2. The IC2 generates sine by frequency between 1Hz to 10 Hz by adjust at P2.
The output level and the depth of modulation adjusted with P3. The switch S1 use to open or close the modulation.
Parts you will need
T1,T1___________TUN__or BC547_____45V 100mA NPN Transistor
R1,R2,R11,R12,R23_____220K 1/4W Resistors tolerance: 5%
C1___0.1uF 50V ceramic capacitors
C2,C6___1uF 63V Electrolytic capacitors
C3___10uF 63V “__________________”
C6,C7,C8__0.33uF 50V Ceramic capacitors