Alesis HR-16 Magno-Bend

By David Battino, Batmosphere

A supplement to my “Synth Hacks” column in the Fall 2020 issue of Waveform.

HR 16-Cords

This 8×4 patch bay, made with #8-32 machine screws, exposes 28 bend points on the HR-16. I wired the bottom four screws to each other to create a mult, then discovered my DIY magnet-tipped patch cords could stack to create their own mults.

HR 16-Patchbay-Interior

A nut secures the wire to each screw. Also notice the four piezo sensors under the drum pads, a clever way Alesis measured how hard you hit.

HR 16-Chip

You can attach wires to either sound ROM. Typically, HR-16 benders solder them to the bottom of the chip socket. I used wire-wrap instead.

Bend Without Baking

You can get amazing, crunchy sounds from an Alesis HR-16 drum machine by connecting wires between certain pins on its sound ROMs. Because there are 28 pins that work, most people add a 7×4-point patch bay, soldering a wire from each pin to a mono jack on the lid. But I found a faster way: I pried the chip out of its socket, attached wires with a wire-wrap tool, and popped the chip back in.

The “safe” pins on the chip include eight data lines, so I decided to make an 8×4-point patch bay and put the data connections in the top row. It doesn’t matter what goes where, but I got more extreme sounds by connecting data pins to address pins, so grouping them made it easier to remember. (See wiring diagram.)

I drilled holes in the lid, inserted truss-head machine screws, and secured the other end of the wires to the screws with nuts. No soldering required.

Finally, I made magnetic patch cords by jamming 3/8-inch neodymium ring magnets onto RCA cables. (A 12-pack of magnets costs $5 at Home Depot.) I oriented the magnets to repel each other when facing head-on, which lets me stack plugs by sticking the tip of one plug to the back of the other. The cables are so quick to move that I can easily perform rhythmic effects.

HR-16 Circuit-Bending Tips

  1. Avoid pins 1, 22, 24, and 32 (marked in red below). They can crash your HR-16.

  2. Print a template to help drill holes precisely. I stuck the printout to the HR-16’s lid, then hammered the dots with a punch to create a dent for the drill bit to grab.

  3. You can solder to alternate pins on the two sound ROMs to make connections easier.

  4. Magnetic patch cord tip: On some RCA plugs, the ring magnet fit loosely, so I mashed the tip of the plug with pliers to widen it.


HR 16-Sound-ROM



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