Let’s go fuzzy!

So the treble booster is running fine, but the promised demo is still on the to-do-list. But while waiting for that one, let’s take a look at the next project. It’s time to add some fuzziness to this blog.

I once again went for a circuit I found online, this one, to be more precise. It’s basically a traditional fuzz face style circuit, only with some minor changes in components and some extra features. I had to adjust some component values according to what parts I was able to find. Here’s my version of the circuit and the parts used:

The pedal will have controls for attack, smoothness and output volume, with an internal trimpot setting the bias for the second gain stage. It will be housed in a standard aluminum box, and there will be a status led lighting up when the pedal is on. This little led however, combined with the fact that I only had a 2-pole switch (DPDT) available, means I would have to sacrifice the true-bypass feature, or I can use the Millennium Bypass (MB). The MB is a really clever little circuit that allows for true hardware bypass and a status led using a 2-pole switch. It uses FET-switching for the led by taking the leakage current from a diode to “open” the FET which feeds current to the led. I used the Millennium 1 version with some modifications, and it works just fine. The geofex website from where this circuit is taken states that there will be a tiny turn-on time for the led, but I didn’t notice any of this using a ultra bright blue led. I also had to add a 1M resistor after the volume pot to prevent the led from lighting up randomly in off-mode. This will ground the gate of the FET and make sure that the led stays off. For practical reasons the switching curcuit is on a separate board, and the current limiting resistor is soldered directly to the led. The bypass curcuit then looks something like this: (the m.b. lead on the circuit pic connects to the Cont lead on this pic)

I painted the box in a nice green color using Revell email paint (the paint used for model planes).

Once again I used stripboard for the curcuit board, and with some careful planning I managed to fit the board above the pots inside the case. Here’s everything in place inside the box.

And finally, the finished pedal:

(The last picture was taken using a different camera, so the color became a little pale, the first picture is more accurate)

So, how does it sound? Well, it’s no hi-gain pedal, but it has a nice smooth fuzz. The bottom left knob controls the pre-gain. Turning this down clears up the distortion much in the same way as turning down the volume on the guitar does. Bottom right is output volume, and upper right is “attack”, which essentially is a tone control. The one thing I really couldn’t find was a inverse logaritmic potentiometer for this one, and it really has its usable range between 2 and 5 o’clock. Might fix this in the future, but it’s not very high on the to-do-list.

Stay tuned for the video demo!

Edit: updated the “attack” (tone) control to an antilog potentiometer. It was a little hard to come by, but totally worth it. Now the attack control is usable in its entire range. Now I’m thinking about changing capacitors for higher quality stuff. But we’ll see about that…