AY is the nickname of the AY-3-8910 programmable sound generator family. The Amstrad CPC sound processor is more exactly the AY-3-8912. This chip was very popular and was used in a lot of machines.
MSX, ZX Spectrum, Atari, Oric... all used chips from this family (sometimes it was the YM variant instead of AY...). The YM variant differed only in the hardware envelopes where it used 32 steps compared to 16 steps for the AY.
As a result it is still quite popular in the actual Chip Tune movement as a vintage sound processor.
Many Chip Tune sites include AY files.
Alas, the ZX Spectrum is more often used as reference. But a huge library is available.
Amstrad Plus specificity
The Amstrad Plus range include DMA sound channels. Each HSYNC, 1 instruction per active DMA channel is read. Each channel executes an instruction which allowed looping and sending data to AY registers. Each DMA channel is effectively a AY register playlist and once started is executed without CPU intervention. It was meant to reduce the strain on the CPU.
This feature offered extra capabilities including 15 kHz sample playback.
- Datasheet AY-8913 on CPCwiki.
Check the Chip Tune page.
Many emulation softwares do exist in order to play chiptunes from AY-YM on you modern machines.
- ZX spectrum computer sound chip emulator :there!
- Project AY at worldofspectrum.org there!
- Arkos Tracker to compose tunes for CPC on modern PCs : there!
- a lot of projects using tools such as Arduino hardware would include AY chips, as those are widely well known and iconic of so many old school computers... and quite easy to connect on electronic circuits.
- PlayCity : a modern card (2014) that can enable to add 2x AY compatible chips to add 2x3 soundchannels, those AY can have their clokcing set in various frequencies and would benefit from some extra compinents advantages so they don't use that much CPU from the CPC.
Some Chip Tunes sites
- The AY riderz a "famous" Speccy music group.
- YM rockerz... the same concept, but with the YM, so the Atari version.
- ultrasyd.free.fr Ultrasyd's Website.