Build Report: Swollen Pickle (Modified Big Muff Pi)

Some years ago I developed interest in guitar pedal effects and stompboxes in general. Built a Woolly Mammoth that I learned a lot on the subject, then soon after a bunch of TubeScreamer Clones. I did it for personal use and to give to friends. Just as I started the TS projects, a long time fella presented me the Swollen Pickle MkII, a modified version of the famous Big Muff Pi.

The MkII version didn’t had any schematics or PCB layout on the internet. I only found a veroboard version of it, I really don’t like the veroboard layouts because they are clumsy and big. For the first time I used EagleCAD Software and tried to reverse engineer the layout back to the schematics. While still looking for more information I found a discussion with a non tested schematic and suggestions over that one. No working pcb layout though, so I continued to draw the schematic.

After I finished the schematics I started the board layout, like the schematic, I never did it before. It was a completely new experience for me, a mix of trial and error until everything fits on the board. With the finished board layout I had one more step: the enclosure.

After some measurements I chose a Hammond 1590XX for the enclosure and the aluminium etching method. I used the same tone transfer method as used for the PCB, but I ended up using caustic soda instead of ferric chloride. I had some bleeding on the edges because I used tape to mask and some bleeding where the toner didn’t transferred properly, maybe next time I will seal everything with nail polish and use ferric chloride instead. 

With the corrosion done, I sanded everything, painted the bas-relief with black spray, sanded again and applied varnish. I drilled it with my power drill, using one spade bit to start all holes(just the tip) and then used a step cone drill bit to the right size.

Nothing new with the PCB and Pedal assembly. I chose a super bright green LED as status indicator. It gives nice touch to the pedal, but ruined the video.

To the video I just downloaded some bass DI tracks over the internet and reamped them using the pedal.


It was a long and complex project for me. If I had the opportunity to redo anything today I would test the aluminium etching on a small scale first. The Eagle CAD part was tiring, but insightful. As for the video the LED ruined it, but I was so tired and wanted to publish something, so I didn’t record another take.

You can download the used Eagle files, ready to transfer pcb layout and partlist on my GitHub repository.

Discoveries of the Month – January/2017

You may have noticed the lack of posts. It has been a very busy month and when I  got some free time I focused on some personal projects. But I got tons of drafts being worked and some experiments to show.

Web Development

Flexible Boxes by Will StoneOne of the dozens generators/playgrounds for CSS3 Flexboxes.


Landell de MouraPriest and scientist. Studied, along Marconi, Popov, Hertz, Brandy, Lodge, and many others, radio transmissions.
Music Macro Language: A music description language used in sequencing music on computer and video game systems.


Velvet Acid ChristElectro-industrial band from Colorado that mixes a bunch of genres.

YouTube Channels:

wingsNpawsTeaches and gives tips of how to train parrots and dogs.
Michael New: Lessons on music theory and how to write music.
I Like To Make Stuff: Woodworking, welding, 3d printing, electronics… this guy works with every sort of thing.
Idea. Sketch. Build.: Small and new channel about woodworking. This guy has some neat solutions for those who don’t have a fully equiped wordshop.
Bisqwit: C++, ASM, Chiptune, Game password crackers. This guy codes everykind of nerd stuff.

Discoveries of the Month – December/2016

Greetings! The time for that post for the last day of the month. Also the last day of the year, hope you guys have a happy new year!

Web Development

CSS GridCSS Grid is going to become supported-by-default in Chrome and Firefox in March of 2017. Checkout the link for more information.


ShellCheck: Find bugs in your shell scripts.
mdless: A utility that provides a formatted and highlighted view of Markdown files in Terminal.
bropages: Similar to man pages, bro pages are concise examples of using command line programs.
commandlinefuCommand-line snippets repository with rating system.


Wendy Carlos(Walter Carlos): Well known composer of A Clockwork Orange soundtrack. I never took time to listen to her albums. Switched-On Bach and The Well-Tempered Synthesizer are wonderful pieces, a must for classical music and analog synthesizer lovers.
Saturndust: Brazilian Space Doom band.
Isao Tomita: Inspired by Wendy Carlos and with similar work. Another Moog grinder for analog synthesizer lovers, his early works consist on covers of rock artists.

YouTube Channels:

Professor LeonardThis guy is doing for Math (Advanced) what Stephen Hawking did for Physics – Make it accessible to the average person.
Adam Neely: Bass lessons and deep music theory researches.
Grant ThompsonDIY, lifehacks, explosions and useless stuff. Expect anything, he honors his name “The King of Random”.