Friday, June 17, 2011

DIY analog sequencer from 2006

I just found a directory tree full of pictures of my old creations. There's many strange, forgotten instruments and sound samples. I'll post them from time to time.

Let's start from one of the craziest.

This one is a 4-channel, 10 step analog sequencer. I still have it around.

Now that's just crazy...
The idea started back when I was 18. I had this vision of creating a sequencer-based tremolo for the guitar. I got it after hearing the song Stüldt Håjt from Kingston Wall (youtube link), I couldn't help but think how cool a hardware effect like that would be to have around. Actually I didn't like the song all that much, I just couldn't help but think about the guitar effect.

It took me three years until I realized that I could finally do it. The device would be modular and I could use it also to trigger whatever else I wanted it to, like some toy synths or other shit.

Of course, now that I look at it, I could do it better, and would go definitely digital, with some fancy LCD screen, unlimited steps, and stuff like that. And still, it would be a breeze to create, compared to all that soldering I had to go through with this clicking analog beast.

The thing is powered by a 4066 decade counter that is clocked by a 555 timer. The circuit is very simple but all the switches took a fucking long time to solder. Everything is enclosed in the shell of some old toy computer my then-girlfriend gave for me to hack.

Here's a feature list I wrote back then:
- Selectable pattern size with min. 2 and max. 10 beats
- 4 channels:
    - 2 channels with two outputs each
    - 2 channels with two outputs each, one output being inverted
- 10 LED display
- Fine & coarse BPM knobs

I had my reasons to put inverted relay outputs (normally closed) there, I was hoping that when combining a normally opened and a normally closed relay output, I could maybe trigger some sounds on each beat. I never got around to test this, though... I don't think it even works because of the extremely small time it takes for the relay to switch.

For those asking, I don't have the full schematic anywhere. That is because I never made one. Back then, I was a bit unorganized in my DIY projects. Anyway, I have some bits and pieces of the schematic, and an old write-up of the whole project. If there's enough interest, I might do some research and eventually post instructions.

Well, here's pics I found of the creation process.

Internals of the sequencer. On the left is the main circuit board. On the right is the relay board and the RCA outputs.
I remember taking the RCA outputs from some old stereo amplifier I found in the trash... I still use a lot of recycled parts in my projects.

Here's the insides combined. There seems to be some little additional breakout board on the right.
A dark picture of the unfinished case.
Beginning of the soldering nightmare...

Still missing the beat size selection switches and the BPM knobs.

All done! It was a pain in the ass...
When making the device, I left no way to open the case without cutting the wires to the control panel. I drilled a hole in the case, put the wires through, left no extra and just soldered it all to place. That's why I can't even find out the exact schematic anymore...

The set-up to achieve a sequenced tremolo guitar effect.
The cone with the yellow "egg" is an input/output box, which takes the signal through and RCA plug to a relay, which is controlled by the sequencer. The signal is taken to the device on the right, which is a very simple guitar amplifier I built. The guitar amp circuit is enclosed in an OLD Phillips answering machine thingie.

And here's the real beef. It's a sample of me playing a guitar through the above set-up, just before taking that picture, somewhere in 2006. I just used some cheap 5€ dynamic microphone. If you listen closely, you can hear the relays clicking inside the sequencer.

I'm still very pleased to hear this effect, even though I really haven't used the device for almost anything after recording this 42 sec clip. Well, I have sequenced a (very shitty) toy synth with it, but I don't have any samples of that... Maybe I should make some.

Stay tuned...

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