[Gijs Gieskes] is certainly no stranger to hacked cassette players, but his latest triumph may well be the most approachable project for anyone looking to explore the world of unorthodox tape unspooling. By attaching a fairly simple add-on PCB to a modern portable cassette player, the user is able to modify the playback speed of the tape at will. The skillful application of such temporal distortions leads to wonderfully abstract results.

The board that [Gijs] has come up with uses four potentiometers and matching push buttons to allow the user to set different playback speeds that they can engage with the push of the button. There’s also a fifth potentiometer to augment the “global” speed as well as an override switch. During playback, these controls can be used to arbitrarily tweak and augment the sound of samples contained on a the looping cassette.

If that’s a little hard to conceptualize, don’t worry. [Gijs] has provided some examples of how the the rapid adjustment of playback speed offered by this “Zachtkind” can add a fascinating level of complexity to sounds and melodies. The assembled player is available for purchase ready to go, but he also provides kits and a detailed installation guide for those who’d rather build it themselves.

Going all the way back to 2005, [Gijs] and his incredible creations have been a staple of Hackaday. From the Arduino video sampler to the array of oddly musical analog clocks, we never cease to be in awe of this exceptionally prolific hacker.