AY-3-8912(a)

The ay-3-8912(a) is a sound renerating chip that is build in in severall 128kb types off zx spectrum but also as seperate board for 48k(emulation) It uses different ports on different boards like TS2068 (w/ clock 1.76475Mhz)(*) or european spectrums.

(*)Sinclair Computer Hardware Factsheet