Skrasoft Dev Blog

It's always good to have spares

You might wonder, “Why so many chips? Are those all going into one single 1000-voice ultimate chip synth? Is mortality really a limitation, or is it a freedom from this ‘mortal’ coil?”

The answer to all of those is that I do plan to sell finished versions of these designs. I wanted to do kits for a while, but it is too time-consuming to make DIY solutions to all the digital work involved here. On the other hand, if I can get a streamlined manufacturing process then I can sell finished modules for less than what I would’ve been able to sell kits for. I can also fit more into less space using surface mount parts.

The definite designs are:

Pokey.synth analog module

Pokey MIDI

Nintendo analog module

Nintendo MIDI

YM2413 analog module

I have some plans together for a monster SID synth module with ridiculous features, but I don’t think anyone would be willing to pay what it would cost. Also, it would take up two full rack spaces.

Sound Clip One

Sound Clip Two

Sound Clip Three

Yamaha’s YM2413 is a neat little FM chip used in the MSX sound expansion board. It was also in some very cheap keyboards back in the day. Thanks to its widespread consumption, enough went into circulation that they are still pretty easy to find. Another benefit is simplicity. It has only a single custom voice, lending itself well to a monophonic synth module without wasting much horsepower.

Friday I had the chip “running” as far as taking data and giving sound. It is not behaving according to the data sheet at all, though, so sadly my process is flawed somewhere. To make sure the chip was at least taking data and doing something, I made a simple loop to write every possible combination of values to the registers. The sound clips up top ensued. They are mostly noise, so watch your speakers!