808 Drums!

Modular Drum Machine?

It was yet another boring afternoon at work. I ended up searching for some interesting DIY eurorack kits. I had never considered adding any drum stuff to my modular synth. I have the not so perfect Akai Howling Wolf drum machine in my setup and have been somewhat disappointed with the kick drum of the unit. So when I found the cheap Sound Force 808 kick diy kit I just couldn't resist. They also have 808 snare kit available so of course I had to get both.

Weird-Valued Vertical Resistors

I usually start all pcb builds by soldering the resistors. They are easy to install and are the lowest components. Unfortunately these boards are designed for smaller resistor components. They can be built with normal through-hole resistors but everything needs to be installed vertically. This makes soldering much slower and more painful.

I have plenty of resistors and capacitors around and these boards don't use any exotic ICs so I thought I could build these without ordering any components. Unfortunately these boards use some very rare resistor and capacitor values so eventually I just had to go and order the exact components. I wish I had done that already in the beginning as the "three resistors in series" hacks are definitely not worth it.

First components soldered. Starting to realize how painful it is to mount all resistors vertically.

These modules use some really unusual resistor values. I first tried to cope with what I had but eventually ended up ordering the exact components. Hacks like these are not worth it!

Arrrrgh!

The mechanical construction is really good. PCB is nicely fixed to the panel with the pots.

The Result

After all the component struggle I managed to get both boards up and running. The end result is nice. Modules are robust and look good. Some of the pots seem to work in a weird way though. (Pitch goes up when tune pot is turned down or so.) I don't know if it's a mistake in the design or just in my build. Anyway, it works so I really don't care.

Kick ready!

Snare too!

The kit consists of panel, main pcb and a small connector pcb attached with a cable. Cable was included in the kit.

The Sound

I have never even seen a real TR-808 drum machine. I have played around with some software versions and sample kits but really don't know what the real deal sounds like so I cannot comment how close these are. Anyway, I love the kick. It's so much punchier than the Akai Howling wolf and gets even better when connected to a Doepfer A-116 waveform processor for some aggressive distortion. I use this kick all the time now. I even started considering a modification to the Howling Wolf to get gate signals out and just trigger drum modules from the sequencer.

I don't like the snare as much as I like the kick. It doesn't sound that special and actually sounds like it's slightly broken with some settings. I might have some errors in my unit. Need to check it more thoroughly at some point.

Next I would like to find a cheap and good sounding hihat module and maybe a simple drum sequencer in eurorack format. Then I could get rid of the howling wolf completely.