The Bazz Fuss

You know a project’s been lingering too long when your son – who couldn’t care less about guitar or effects pedals – wonders into your office one day, points to a jumble of wires and components, and asks “are you ever going to finish this thing?”

That “thing” is the bazz fuss circuit I soldered onto a perfboard several months ago. I had watched Paul of DIY Guitar Pedals put together his “5 minute fuzz” effect and had read an article on Seymour Duncan’s site about building the effect with some nice mods to the original circuit. Some more details about the original effect are available here, but essentially it seems Christian Hemmo developed a fuzz effect for the bass that used the fewest components possible (and still generate a decent effect, anyway). The design is extremely elegant and produces a nice “dirt” fuzz effect (probably perfect for bass guitar). Hemmo’s original site is long lost on the internet (ah,! – still available via, though, of course) but his circuit lives on.

The bazz fuss effect on a breadboard with labeled controls

I built my first attempt at a Bazz Fuss effect by wiring the components in my breadboard, following along with the Seymour Duncan article (seriously cannot recommend that article enough). I went through the various iterations on the breadboard in the article and ended up with the “modded” version there-in. I even tried adding a battery sag control as well, to emulate a battery losing its charge which sounds good on some effects. This particular effect is one in which it basically just no longer has enough voltage to make any noise, so it just kills the sound below that threshold. This is the breadboarded effect that I used to demonstrate my test rig, in fact.

Inspired by this Make video on circuit skills on using perfboard to quickly build a circuit, I figured I’d try soldering the components down. I just bent over some longer leads and soldered them to make more-or-less a ground rail and a power rail, and then built the circuit from there. I sketched it all out on graph paper before hand, but the circuit is so simple I had nearly half of the perfboard free after soldering everything.

My initial perfboard circuit

And so this sat on my shelf for months until my son asked about it. I figured I really did need to wrap this thing up before moving on to any other projects. I had purchased a blue powder-coated enclosure for my tremelo kit pedal and had already transferred the guts of that effect to its new home. So I had an enclosure that only needed a couple of holes made larger.

I should note here that I use external nut AC jacks on all my builds. Yes, they stick out further and are less attractive. But, here’s my reasoning:

  • all the other external components (except LEDs) already have external nuts
  • I found that the extra 1/4″ of depth provided using an external nut AC jack really helped in a 1590A enclosure, such as my Micro Amp clone
  • most importantly: I can pull the guts of a pedal out without having to cut a single wire; nothing is actually even necessarily wired after going into the enclosure at all this way!

In the spirit of recycling old parts, one of the resistors I had pulled from my CryBaby Wah mod was the right value for the LED resistor! I don’t even know why I bothered saving it, but I was glad I did. I use some of the spare space on the perfboard to mount the LED and the resistor. I used a bit of hot glue to hold the LED in place (in fact, that’s the only thing holding the entire board in place!).

The LED hot glued into the enclosure – note the old tan, 5% tolerance resistor

I did use sockets for both the diode and the transistor. I don’t know that I’ll ever swap them out, but I have that option. In fact, Paul of DIY Guitar Pedals has an entire video just comparing different combinations. Though my pedal doesn’t have a ton of gain, it sounds pretty good using the BAT41 diode and MPSA13 transistor. You can see where I used a sharpie to mark the orientation for both, as well, because I won’t remember should I ever want to swap them out. On the subject of troubleshooting, I spent a lot of time troubleshooting this build only to ultimately determine the A100k put for the volume was just a bad pot! So I definitely don’t want any more headaches trying to figure out the correct orientation for a diode or transistor. I even got so paranoid, I lined the back of the pots and the back of the perfboad with electrical tape to ensure nothing shorts!

Overall, it’s not the prettiest build I’ve done but it is complete, works, and sounds pretty good. I’m proud that I was able to layout the components in an efficient way (which is of course important to printed circuit board layouts, which I hope to try out at some point).

The finished wiring. What a rat’s nest!

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