20-11-2019, 08:05 PM
(13-11-2019, 04:24 PM)elpiggio Wrote: I'd like to build a better quality 8-bit DAC.
Hi elpiggio
Welcome aboard!
Someone says to get great quality sounds out a of microbee using devices from that era you can use the AM6070 DAC (DAC-76) as used in the famous Linn Drum.
Unfortunately these are now hard and expensive to get. (Just like the SID chips for for the Commodore 64).
Like the microbee the Linn Drum uses a Z80. It just uses its Z80 to drives lots of AM6070s with EPROM stored sound samples.
An alternative to get great sounds out of a microbee from that era is to use a microbee MIDI interface.
There are at least two versions - one uses the SCC on a DRAM motherboard and the other uses a Roland MPU401.
The SCC method is the most economic and easiest way.
All one needs to do is hook up a suitable optocoupler (e.g. 6N138), a TTL open collector buffer(e.g. 7407), a diode, a few resistors and two DIN sockets.
Just configure the SCC for 31,250bps, hook up a MIDI instrument or more and away you go!
To play sound samples of your choice the cheapest way is to use an AKAI MPX8 or MPX16.
This allows the microbee to play a bunch of SDCard stored .WAV samples.
(The MPX16 has a built in microphone making it easy to record .WAV samples without needing a PC.)
Good Luck!