Super Simple Dual Sine, Triangle, and Square Wave LFO

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I am finding that the ambient electronic music I am creating is requiring lots of LFOs. Here is a really simple yet very useful Sine, Triangle and Square Wave LFO. In low range this thing will take minutes to cycle when turned all the way down. I put the rate indicators on as an afterthought, thus the whacky resistor numbers. The reason this is dual is because I couldn't stand leaving a perfectly good half of a LM13700 sitting idle. The theory of the oscillator is the same as the Super Simple Ramp LFO except as you can see there is no diode and 1K resistor to yank the inverting input of IC1-D around so the integrator's output goes up and down at the same rate. The LM13700 provides sine shaping. I plan to try to use the second LM13700 to provide voltage control by essentially replacing R4 with one wired as a voltage controlled tranconductance amp.

Dual Sine, Triangle, and Square Wave LFO



Dual Sine, Triangle, and Square Wave LFO PCB Layout (Component Side View)

Dual Sine, Triangle, and Square Wave LFO Parts Placement

Dual Sine, Triangle, and Square Wave LFO Parts List
(Thanks to Colin Raffel)

Qty Description Value Name
2 Resistor, 1/4 Watt 3M R1, R19
2 Resistor, 1/4 Watt 200k R2, R20
4 Resistor, 1/4 Watt 10k R3, R7, R21, R25
6 Resistor, 1/4 Watt 1M R4, R13, R15, R22, R31, R33
2 Pot, Linear 50k R5, R23
6 Resistor, 1/4 Watt 100k R6, R14, R24, R32, R91, R93
2 Resistor, 1/4 Watt 220ohm R8, R26
6 Resistor, 1/4 Watt 1k R9, R16, R17, R27, R34, R35
2 Resistor, 1/4 Watt 47k R10, R28
2 Resistor, 1/4 Watt 470k R11, R29
2 Resistor, 1/4 Watt 390k R12, R30
2 Resistor, 1/4 Watt 4.7k R18, R36
2 Resistor, 1/4 Watt 3k R90, R92
2 Nonpolar Cap 2uF C1, C6
2 Nonpolar Cap .02uF C2, C7
2 Polarized Cap 1uF C3, C4
2 Nonpolar Cap .01uf C5, C8
2 Nonpolar Cap 47pF C9, C10
1 Quad Op Amp TL084 IC1
1 Dual OTA LM13700 IC2
2 Transistor 2n3904 Q1, Q2
2 LED None CR1, CR2
2 Toggle Switch SPST S1, S2