Well if it rumbles as much as a Harley he will be looking for a lot of spare parts
Take a couple of intake valves from a Harley-Davison Shovelhead engine, a few blocks of (thick) plywood, a cheap stepper motor and a handful of other leftovers and what do you get? Why, a mellow sounding, home-made record player, of course.
The Altmann DIY turntable and tone-arm are built from such parts. The Harley valves make up the bearing, the wood goes into the base and the platter, and the stepper motor is fed a sine wave to keep it spinning at a constant speed. Wait, what? A sine wave?
Charles Altmann, for whom the setup is named, needed an analog way to run the stepper motor at a constant speed. By generating a 50Hz sine wave on a computer, running that to an old amplifier and then connecting the speaker outputs from that to the two coils of the stepper motor, Charles can get the motor running at just the right speed to turn the platter at 33 1/3 rpm. Tweaking the frequency allows fine adjustment if you need it, and you could then load the resulting sound file onto an MP3 player.
The whole project is delightfully Rube Goldberg, which is of course why we love it. Charles says the sound is pretty good, but we’re just as interested in his workbench. Take a look at the picture again and tell us you’re not jealous, too.