DB-1 Dual analog drum module

The DB-1 was the first instrument I built for serious music making. It’s a culmination of a lot of Thomas Henry design ideas, taken from the excellent Scott Stites blog and found in his books reprints published by Magic Smoke.

For the longest time I craved a fully controllable analog drum voice, but couldn’t get myself to spend the money on a JoMox or something of that level. Alternatively, to invest in modulars would mean a good 1K or more for a basic kit. I did modify the 606 by this point, which made it a lot more useable, but still a very 606 sounding machine. I wanted a lot more control!

The DB-1 consists of two analog drum voices suited for bass drum, snare, toms, woodblocks and all sorts of similar noises. Each voice uses a different design. I also added a few of my own touches:

Voice A is based off the Bass++ as the VCO core, with the addition of noise, a noise ‘squarer’ circuit I found in an old Penfold book, followed by a passive filter. The VCO portion of the voice can be controlled via an external CV input.

Voice B is based off a snare drum design found in TH’s Electronic Drum Cookbook. The core of the VCO uses an LM566 IC (not to be confused with the LM555 & LM556 timer ICs). This VCO IC has totally vanished from stores bins as production for it ceased years ago, but you can still find it on EBay for about $10. I was lucky enough to find a handfull in a local electronics store. They seemed to have missed the fact that this IC is now worth something and sold me the 10 pieces they had left for about $20.

The block diagrams below illustrate the voices structures.

I added a ‘Tie’ function, allowing both voices to be triggered from the same input. This option is great for stereo sounds and complex mono sounds.

It’s a wonderful sounding box, very versatile and very useful.

I envisioned the DB-1 to be the first in a drums modules series, with two more dual voiced boxes for percussive uses in mind. The DB-2 will be based on a combination of additive and subtractive synthesis, and will be more useful for noises and other funky sounds, and the DB-3 will take care of all the hi hat/cymbal duties.

I could then use these 3 boxes together as a kit.

Below is a demo video I made for it. It’s a bit slow but I love the bit at the end! 🙂


4 thoughts on “DB-1 Dual analog drum module

  1. Jaime

    Hum … Génial … You do it well … I don t know if you make that s machines to buy them … I m near to Avignon ..south France… It s will be a pleasure to have new about … You … Your products … Or to Know somme one playing with …

    analog machines for ever…to boost … Sound systems…

    Jaime …Misantrope Crew…

  2. admin Post author

    Hey Jaime,
    I’m in the process of figuring all this stuff out.
    Stay tuned – any new developments will be posted here! 🙂

  3. Anton

    Great Earo, Is it possible to ask build one for me ?
    Please let me know,

    • admin Post author

      Hi Anton,
      I may be building a couple more of these, as I’ve received a few requests for them. Please send me your e-mail and I’ll keep you posted.

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