Synthrotek APC HANDELDAn easy-to-build, all board-mounted APC! With more stepped tones and better bass response, the APC Handheld is a new take on a classic circuit!

Originally designed by DIY electronics guru Forrest Mims III as the “Stepped Tone Generator,” the Atari Punk Console is one of the most famous and recognizable Lo-Fi synth circuits ever. Using a single 556 dual timer IC with minimal part count, the Atari Punk Console circuit is a solid, time-tested noise generator capable of outrageous square wave madness!


  • Easy build for beginners!
  • Better bass response (lower duty cycle than original)
  • More steps in between the original stepped tones
  • Dual power supplies: use a 9V battery or an AC Adapter rated at 5-12V 200mA (center negative polarity, not included); DC Jack allows for power switching so that battery power is only enabled when there is no AC Adapter plugged in
  • Control Voltage (CV) input allows sequencers and waveform generators to expand the sonic capabilities of the Atari Punk Console from drone to arpeggiated dynamism
  • Use any variable voltage source from 0-Supply Voltage for some glitchy goodness!
  • 3 potentiometer controls – Pulse Width and Frequency contour the tone while the Volume control sets your output level just right
  • Uses 1/4″ mono instrument jacks