Posted By
MMS
on 2023-02-05
03:25:03
 |  Re: Covox Speech Thing - parallel port adapter
Actually you do not need the covox Speech thing.
It is simply an 8 bit DAC. I built mine at the university based on a Ferranti ZN426E IC.
I am really lame in hardware, so if I could do it, anyone can 
(you can do the same thing with a resistance ladder too, but it will have more distorsion than a DAC IC).
I am after a relocation, may look for my circuit, I had it near to me for a long time. But not now.
Anyhow, with the below two diagrams and with the help of SVS Ultimate map you can connect it to Plus/4 User port too (you can find a User port comparison between C64 and Plus/4)
The connection could be easy, just need the PC Covox circuit, samplepanel, a Centronics port connector, the User port connector (I have 5 maybe?) and some Dupont cables. hopefully the User port could provide enough juice for the IC ith the 0.1A limit. I used the PC's keyboard connector with a small adapter as a power source. (red wire on the picture)
I am not sure about the signal levels, if our TTL on User port is OK for the Covox too?
On PC it worked pretty well under some games, like Pinball Dreams, and played nice the MOD musics on PC.
Certainly after buying my Diamond Monster and GUS cards I've never looked back, especially as the newer Windows version killed the direct printer data transfer.
Probably Windows ME is the last Opsystem that let the Covox work properly.
I know it is just 8 bit, but sounds nice with ZN426E. And certainly sounds better than the TED digi, and requires less CPU power than the inner conversion to fit to TED.
The huge samples in MODs could be a problem for our platform (without REU), but the smallest chipmusic MODs may fit into our memory with 20-30KB size.
https://www.youtube.com/watch?v=GH7eUlri4yM
The C64 Soundmax is the same thing, just with stereo output. and made with a currently available, cheaper TLC4226 IC.
(on ebay you can find cheap Ferranti ZN426E or 428E ICs, but most of them are fake, with reprinted surface)
https://www.youtube.com/watch?v=Gn1w9tJHtAQ
And the complete history with programs:
https://c64os.com/buyersguide/?feature=digimax
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