Gakken SX-150

via this auction
"Features
* Size: 4.5" x 6"
* Controls for LFO, pitch envelope, frequency cutoff, resonance, and attack/decay
* Slide controller (pen type electrode)
* Output and external input 1/8" jacks
* Small built-in speaker
* Runs on 4 AA batteries (not included)

Putting it together
Assembly of the kit requires little work - the circuit board comes fully assembled, i just mounted it to the panel and connected the stylus control strip. Power is provided by 4 AA batteries and a small speaker is included in the design. I highly suggest connecting the output to external amplification (this little guy really does sound quite good!). The "external source" jack accepts an amplified signal and converts its frequency into pitch control. Controls for LFO, pitch envelope, frequency cutoff, and attack/decay are included. Each potentiometer gives a wide range of response, so you have a relatively large amount of control over the sound."

Mod me
The simple design seems to suggest that the SX-150 wants/needs to be modded, hacked, and/or customized. Using the stylus/pitch-strip control only gives you a taste of the good sounds you can get from the kit. The SX-150 kit is very easy to use and some modding ideas are bound to come to mind should you get your hands on one. At the very least, you can choose from a number of included decorative decals - and at the more advanced end, schematic and code for using MIDI input has already been posted. I'm sure more sweet DIY add-ons are in the works - very awesome.

The Controller F - A touch pen generates CV and Gate.
- Also has a tiny extenal input that does F/V conversion.
(but also responds to amplitude :-).
VCO F Has saw-tooth output
VCF F Sullen-Key type 12dB/Oct filter. Very much like Korg MS-20 filter.
Envelope Generator F AD type.
LFO F Two output waveforms: triangular and rectangular.
Output F "

signal flow diagram below