Compared to ZX spectrum the Amstrad clearly failed to impose itself on the AY-scene. Perhaps because it was less popular worldwide, perhaps because it lacks a built-in Midi Port.
Also it is to notice that Amstrad CPC's AY soundchip has a lower clock than most of its competitor, running @1mhz while Atari ST is @2mhz or ZX spectrum128 @1.77mhz
To have MIDI on an Amstrad an external peripheral is needed, being somewhat less reliable than a directly built-in connector.
As a result, not a lot of Chip-Tune bands actually use an Amstrad computer for live performances (but the ZX spectrums from Amstrad...). Worth of notice is the french [[Ultrasyd]] who may uses an Amstrad CPC6128 alongside Atari ST and Nintendo Gameboy and actually produced some tunes for the CPC scene as well.
This is somewhat of a shame, as the 6128+ would be a good machine for such purpose thanks to it's DMA channels and the possibility to put software on Cartridge/Rom.