Electrophones > Analogue electronic instruments, modules and components > Analogue synthesizers and other electronic instruments with thermionic valve (vacuum-tube) or solid state circuitry (transistor and/or analogue integrated circuitry) generating and/or processing electric sound signals > Analogue synthesizers and other electronic instruments with solid state circuitry (transistor and/or analogue integrated circuitry) generating and/or processing electric sound signals > Analogue synthesizers with solid state circuitry based devices generating and processing electric sound signals using additive synthesis