it’s based off a drawing of a BigMuffÏ schematic. same design but made all the part values different… bigger caps for more bass, unmatched parts for weirdness, etc…

used 4 magic germanium transistors (AC187). they’re magic because they change their electrical characteristics (ie sound) according to your mood.
actually, that’s not true. but they do change with the temperature. and so do i, so close enough.

i got a bunch of silicon transistors at the same time and measured the gain of everything. for some reason the germanium ones were all much better matched than the silicon ones which were all over the map. that’s not usually supposed to be the case but there you are. the silicon ones did sound pretty crazy but playing 2 notes at the same time would crap everything out so i’ll just have to save those for something else.

i added trim pots between the emitter of each transistor and ground so you can tune the pedal. i ended up with something that kind of phazes out and in with itself, and the tuning was mainly used to select the speed at which this happens.

soundsample:

http://www.mediumrecords.com/random/wp-content/yuri/mufftest001128K_Copy.mp3

the sample is bass guitar through pedal direct into computer. starts with clean sound. then distortion on lowest ‘sustain’ setting (that’s the big knob on top). then stuff get turned up a bit. then tone is changed to low and back. and that’s it.

sounds kind of crappy. had it sounding more crappy before but i left it sitting on the breadboard too long and kept trying to ”refine’ what i had.. bad idea.. next time i’m sticking to quick and dirty. (btw i tried some better quality caps and things and the cheap crappy components sounded way more appealing.)

besides that, if there’s anything i learned from making this thing, it’s that 2nd-hand salad bowls make for great cases and the tops of bicycle-bells made for great knobs. (you can find those on the street all over the place here)

but here’s construction photos:

must drill holes. stainless-steel is pretty tough stuff don’t you know. bedknob used for getting the angles with drill.

had to cook to red-hot temperature. not to clean it or make it look neat but because it make a wicked sound when you throw it in water.

so. looks something like a sputnik to me… but i’m sure i’ve seen this thing on doctor who before.

little shock-mount for the circuit-board. oh, i should have made a photo of the underside of the board, it’s such a total mess, everything is just gobbed together with tons of solder.

tuning the thing.

testing

done.

the end / fin

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