Synthesizer on Instagram: "Maplin 5600s Synthesizer Ad - (1970’s) An Australian designer, Trevor G Marshall, created a kit (half-analog, half-digital) called the ETI 4600. The sounds were published in October 1973 in the Australian magazine “Electronics Today International”. The plans were bought by the English company Maplin Electronics, which marketed Maplin 5600 what was available in a wooden frame with a keyboard. The sound of the instrument does unique and really fat, and the semi modular a