From http://faqs.cs.uu.nl/na-dir/amstrad8bit-faq.html:
A8.1.1.2) Futur's 10/31/99
Futur's is a french group, they do many things. They bring you the Soundplayer (a better Digiblaster). It connects on the printer port. The Soundplayer is used by Protracker and Digitracker. You can do it yourself for about 30 FF of electronic components. The electronic plan is in the paper zine Quasar issue 9, see A9.1.3. With this little marvellous thing, you can have 8bit samples, instead of 4bit samples. The SoundPlayer+ is a better SoundPlayer, which can include Virtual Net 96 (see A10.5) for 10 FF more, or which can use a CPC+ port instead of the normal CPC printer port.
The SoundPlayer II now exists. It connects on the expansion port and permits to make mono 8 bits/22KHz digitalized sound. It offers one more port to connect a second Soundplayer (for stereo) or to free the printer port.
For ordering a SoundPlayer+ or 2, see A9.1.3
see http://www.chez.com/futurs or http://www.i-france.com/futurs