+ - + - + - + - a b c d e f g h i j 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 25 26 27 28 24 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 25 26 27 28 24 29 30 a b c d e f g h i j 576 Modulator I discovered the 567 tone decode chip from an old hemmo project. The chip itself was used back in the day to decode touch tone frequencies on phones. When misused as a stompbox effects generator, the 567 can yield some interesting sounds. This project is a simple adaptation of the 576 to produce a variable modulation effect that goes from ring modulator to tremolo. beavis board project A100K Volume in out Mods! There are many different configurations of inputs and outputs for this chip. Although the datasheet specifies one input and one output, I’ve used pins 1,2 and 3 for inputs and outputs with different sonic results. You can change the values if the input and output caps (C1 and C2) to lower values to remove bass. The VR1 and C3 parts set the operating frequency of the circuit, experiment with different values here. 10uf + 567 1 7 2 C2 10uF C4 100nF 3 4 VR2 B50K (filter) C5 100nF 6 5 VR1 B100K (mod) C3 10uF U1 LM567 C1 10uF 9 volts + Input VR3 A100K (volume) Output 100nF 10uf + B100K Mod 10uf + 100nF B50K Filter revision: 1.0 ● 28 may 2008 ● © 2008 beavis audio research