The Sequential Circuits Prophet 600 is a 6-voice polyphonic analog synthesizer released in 1982.  It was the first commercially available synth to include MIDI functionality.  The 600's analog voice's are controlled by a Zilog Z80 CPU. Though state-of-the-art at the time of its release, the Z80's specs means the synth feels limited and slow to respond to changes compared to modern instruments.

Luckily, synthesizer enthusiast & engineer GliGli has written new firmware for the Prophet 600, designed to run on a Teensy++ development board.  Replacing the 600's Z80 with a Teensy++ running Gligli's firmware adds a long list of features to the classic synth, including:

• Increased resolution for sound parameters
• Faster, smoother amplifier and filter envelope generators
• New LFO function generator with a wider range
• Dedicated vibrato
• Unison detune
• Mix Overdrive
• Full Midi In control of parameters
• Improved tuning procedure

Swapping out the Z80 for the Teensy++ is a relatively simple process, and can easily be reversed if you decide you prefer the 600's original functionality.  Some basic modifications will need to be made to the Teensy++ board before usage. 

What you'll need

• Prophet 600 Synthesizer
• Teensy++
• Solid core jumper wire
• IC puller/extractor
• Soldering iron & solder
• Needle nose pliers
• Solderless breadboard
• Mini USB cable
• X-acto knife or razor blade
• Conductive foam & antistatic bag (for storing old microcontroller)

Once you have all tools & materials ready, we can move on to programming the Teensy++.