Circuit design and hardware implementation of an analog synthesizer

Abstract: Since the heyday of analogue synthesizers in the 70's, they have largely been replaced by digital hardware and software synthesizers. However, in recent years, there has been a revival in analogue designs, possibly due to its ``warmer" sound. This projects aims to take part of this renewal by building a simple analogue synth design with the most basic modules (e.g. oscillators, filters, mixers, amplifier), accompanied by a step sequencer for programming melodies. This will be done by designing circuits and implementing them on breadboards. The circuits were designed with inspiration from various online resources, along with theoretical analysis and simulation software for complex circuitry. The result is a fully functional synthesizer with four sawtooth oscillators. The only modules missing from the initial design are battery support and a line out output for recording the output of the synthesizer. The pitch specification was met as the oscillator did not differ from the expected frequency by more than $\pm$15 cents (hundredths of a semitone), for a range of five octaves. Some possible improvements include better step sequencer user friendliness by installing a display to indicate the notes, more robustness by implementing the synth on a circuit board instead of breadboard. Some improvements can be made for the synth. For example, a display for the step sequencer would facilitate melody programming. Moreover, implementing the synth on a circuit board instead of breadboards would greatly improve robustness and reduce the risk of sound disruptions.