Woooosh: an analog synthesizer noise module.

• Mar 03, 2021
• edited: Feb 26, 2022

I’ve been interested in analog synthesizers for a while and have been planning to build a modular system of my own. I’ve been messing around with circuits on breadboard for some time and am working on designing 2 of my own modules, which will hopefully be finished soon.

In the meantime I decided to build a white noise oscillator module as a noise source is very useful for a lot of things and I wanted to build something easy and quick with my girlfriend for fun. I’ve been binging Juanito Moore’s youtube videos lately and he has a great video on a pretty simple white noise source that uses an NPN transistor with the collector clipped off to make the noise. René Schmitz also has a similar circuit on his website and Kristian Blåsol has a video on his channel about another one from freenrg.info. I chose Juanito’s circuit because it runs on +/-12V and it has a volume knob, which is handy since I haven’t built a mixer or a VCA yet.

Usually I use stripboard for my projects but we decided to build this one on perfboard because I have a pile of small perfboard PCBs I had accidentally ordered years ago lying around and the circuit is pretty simple to fit on one. We started out by laying out the circuit in DIYLC and this is what we ended up with:

The circuit isn’t as compact as it could be as I wanted to have the least possible jumper wires and an overall clean layout that’s easy to understand. I also color coded the traces: red for +12V, blue for -12V, black for ground and yellow for everything else.

After laying out the circuit it was time to actually build it. We used component legs and bent out paperclips to make the traces, which turned out really well even though my girlfriend, who is a beginner did most of the soldering.

Here are some pictures of the final board:

Front side of the board

Back side of the board

We didn’t solder the transistor into the board but instead put it in a little socket so it’s removable and I can experiment with different transistors in the future if I wish.

And here’s a picture of the finished module:

I built the front panel out of a piece of sheet metal I cut off of an old PC case side panel and used a silver marker to add the text. I didn’t add clear coat on it so by the time I’m writing this the marker has already completely been wiped off. Maybe I’ll make a proper design on it with spray paint and a stencil in the future. I’ll update this page when I do. (Update(2022/02/26): I got a better silver marker and it’s not rubbing of anymore.