The Bucket Brigade
Inside the Boss HA-5 headphone guitar amplifier from 1983. It had built in chorus and delay effects. The chorus came from the Boss CE-3 guitar pedal and used the Matsushita/Panasonic MN3207 Bucket Brigade Device and the accompanying MN3102 clock generator chip. The NEC IC on the left is an analog compander device i.e. it compresses and expands a signal. The Bucket Brigade concept, developed by Philips Research Labs, had a series of on-chip capacitors that charges moved between, based on an external clock cycle. It was also a precursor to the Charge Coupled Device (CCD) that was developed as the first significant semiconductor image sensor.