The PSG chip family is composed of 3 variants: the AY-3-8910 with two 8-bit I/O ports, the AY-3-8912 with one 8-bit I/O port and the AY-3-8913 with no I/O port. In addition to the CPC, these chips were also used in the [[KC Compact]], [[ZX Spectrum]], [[MSX]], [[Oric]], [[Vectrex]], [[Intellivision]] and in the Mockingboard expansion for the [[Apple II]].
The PSG chip competed with Yamaha produced the DCSG SSG (Digital Complex Software-controlled Sound Generator) chip family (SN76489YM2149F, SN94624YM3439, TMS9919YMZ294, YMZ284, YMZ285) by Texas Instrumentswhich is a quasi-clone of the PSG. The DCSG has similar sounding features except main difference is that it does not have any the envelope control counter on the PSG has 16 steps. On the SSG it has twice the steps, happening twice as fast. This chip equips the [[Atari ST]], [[Aleste 520EX]] and that its noise generator [https://www.msx.org/wiki/Yamaha_YM2149 some MSX computers]. It is also used in the [[PlayCity]] expansion. The SSG has its own dedicated channelalso been integrated as a component inside some of the arcade soundchips of the Yamaha OPN family. That's why you can find it in the [[Neo-Geo]] as a component inside the YM2610 soundchip. And the same is true for the OPN3 soundchip of the [[Play2CPC]] expansion.
Toshiba T7766A, Winbond WF19054, JFC 95101 and File KC89C72 are clones of the PSG. [https://wiki.agiri.ninja/sound_chip_clones:index Source]
Yamaha produced the SSG (Software-controlled Sound Generator) The chip family (YM2149F, YM3439, YMZ294, YMZ284, YMZ285) which is a quasi-clone of the PSG. The main difference is that the envelope counter clocked differently depending on the PSG has 16 steps. On the SSG it has twice the steps, happening twice as fast. This chip equips the [[computer: ZX Spectrum: 1773400 Hz ; Pentagon: 1750000 Hz ; MSX: 1789772 Hz ; CPC: 1000000 Hz ; Atari ST]], [[Aleste 520EX]] and [https://www.msx.org/wiki/Yamaha_YM2149 some MSX computers]. It is also used in the [[PlayCity]] expansion.2000000 Hz
The SSG has also been integrated as a component inside some of PSG chip competed with the arcade soundchips of the Yamaha OPN DCSG (Digital Complex Sound Generator) chip family(SN76489, SN94624, TMS9919) by Texas Instruments. That's why you can find The DCSG has similar sounding features except that it in the [[Neo-Geo]] as a component inside the YM2610 soundchip. And the same is true for the OPN3 soundchip of the [[Play2CPC]] expansiondoes not have any envelope control and that its noise generator has its own dedicated channel.
The EPSG (AY-3-8930), used in the Covox Sound Master soundcard on PCs, is a register-compatible evolution of the AY-3-8910: