Tag Archives: beavis

Breadboards and prototyping pedals

As time goes on I become more and more addicted to futzing with pedals, which is a good thing I suppose. But it is tempting to just keep building kits without really knowing whats going on in there. I’ve made attempts to tweak the pedals I’ve built from DIY Effects but only to the extent of messing with clipping diodes. And to be honest they sound great already, so there isn’t much to be done. What I really want is to go back to basics and learn how different parts of the circuit work and also how they interact with others.

So I needed a way to, for example, build a simple transistor gain stage (like the SHO I did before) and perhaps chain it with another one, to see what happens. Or build a generic fuzz and then play with bias values or different transistors. You get the idea. All this is harder to do if you are constantly soldering/desoldering components, so it’s time for breadboards 🙂

This project is nothing magical, just some parts assembly, but it was a lot of fun. I based my version on the Beavis Audio board that you could once buy in kit form. Here’s the link to the Beavis site, and a photo of mine:

The prototyping board

The prototyping board in its first incarnation.

What’s going on?

Power comes in from a small bench supply I have (not shown) via a standard 2.1mm socket on the back of the breakout box. That goes into the 10k pot, which lets you simulate crappy batteries. ALso not visible are the two 1/4′ jacks that serve as guitar in and effect out signals. You can clearly see the 3PDT stomp switch and the smaller toggle. All these connections are present on the connection block which I bolted to the side.

I also added a board on the back with some handy holes drilled in it. These will hold whatever pots and/or switches the circuit might need. Shawn from DIY Effects had done this, and it looked like a great idea, so I stole it 🙂 Here’s his blog entry showing a massively complex circuit on his protoboard. One day I’ll get to this stage!

What’s next?

  • Build a reverb circuit, probably the ‘Box of Hall’ circuit featuring the BTDR-2H reverb module. It should be very simple.
  • Build a generic fuzz-face and then progressively mod the crap out of it to see how it works.
  • Try some cascading gain stages (based on the Z.Vex SHO) to see what following the tube amp topology achieves.
  • Arduino!!! (this is a potential can of worms that will end with a switchable rack system…mark my words)

UPDATE! Here’s the Box of Hall circuit on veroboard. I still used the breadboard rig to hook up to power and I/O. And with great joy I realized that my little Marshall practice amp (if you can even call it that) clips onto the the back quite nicely 🙂

The circuit on overboard, connected to my huge Marshall stack.

The circuit on overboard, connected to my huge Marshall stack.

UPDATE 2: I did a prototype of the classic Fuzz Face. Not much to see, but it’s proof that the breadboard has made it very very easy for me to experiment with different circuits.

Silicon Fuzz-face!

Silicon Fuzz-face!

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