MakerShed is now selling the SX-150 Analog Synthesizer Kit, a $45.99 kit that lets you build a simple synthesizer. 

Here’s a demo video for the SX-150:

There are a lot more SX-150 videos on YouTube, and a lot of people are coming up with SX-150 hacks, too.

Description:

This cool little synth kit is easy to put together, requires no soldering and is easy to hack (see links below). There are no English instructions included (book and kit are in Japanese but beautifully done) but the detailed illustrations are more than enough to easily put this kit together. 4 AA batteries (not included)

Features

• Size: 4.5 x 6 inches
• 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