Sunday, October 15, 2017

The Video Fuzz: a Fuzz Pedal Based on the S9014 Transistor


I built a fuzz pedal for my guitar using parts from an old, off-brand Nintendo accessory called the "Video Shooter" and a broken Fender Frontman amplifier.  The pedal is based on the Bazz Fuss, which is a simple fuzz circuit that is easy to modify.  I wanted to use parts from the Nintendo accessory as much as possible, so I designed the circuit around the accessory's enclosure and the S9014 transistors I found inside.  One S9014 did not put out enough gain to work as a guitar effect, so, after reading this forum thread, I joined two transistors into what is called a "Darlington transistor".  The happy result was sufficient gain and a very well-behaved fuzz pedal.  Unlike some other Bazz Fuss derivatives I have encountered, it doesn't fizzle or sputter when connected to a guitar with high-impedance pickups and or when I roll off the volume on the guitar.  Its gain is moderate.  I call it the "Video Fuzz" in honor of the NES accessory

Since it's so well-behaved, I'm sharing the schematic here in case anyone wants a good starting point for their own fuzzy experimentations:

Video Shooter Fuzz Schematic
If you compare the circuit to the original Bazz Fuss, you'll notice I added a resistor in front of the pot going to the output.  I did this because the output is well above unity gain even with 47k Ohms resistance; I'd never want to use the full range of a 100k Ohm pot.  I added a 2.2k Ohm resistor at at the collector of the transistor to set the fuzz to a level that sounded good to me.  I could have put a pot at the collector to have a two-knob fuzz, but instead I opted to make a one-knob fuzz and control the fuzz level with my guitar's volume knob.  For the switch and jack wiring, I used the wiring shown second to last in DIYStrat: Wiring a Stomp Box. Here is the finished pedal:


This is the fuzz circuit by itself, minus the 50k Ohm pot:

Hand-Soldered, Point-to-Point Wiring!
I won't show you rest of the insides; you've seen enough of the sausage being made.

And here are some sound clips: (1), (2).  Interestingly, when I was first wiring a Bazz Fuss circuit, I connected the collector and the pot to the negative end of a battery but not to ground and the resulting circuit made no distortion and behaved like a buffer. 


5 comments:

Cool beans said...

I made one today and it sounds pretty cool, it also acts like a gate XD

mackwai said...

I wonder why it acts like a gate. Did you use the same schematic, or are there differences? I get a little bit of a gated fuzz effect from my pedal when I turn my guitar's volume down, but not much.

Cool beans said...

yeah its like a gated fuzz when I turn down the volume a bit on my guitar, its a cool feature I think

Anonymous said...

Is that a 3.3 if non polarized cap at the input?

mackwai said...

It's 3.3 microfarads. The capacitor I used is polar, but I don't think it matters whether the capacitor is polarized or not.