Introduction: The Bulldog Face Distortion Pedal DIY

The Bulldog Face is a three transistor pedal modeled after the vintage Fuzz Faces of yesteryear.  This incarnation is a modification of the Ferris State University EET & CNS Department’s EET-211 lab #3.  Please feel free to visit our website for more information on our program:  www.ferris.edu/eet
This is a five part video so that you can focus on any aspect of the project easily.  Some quick specs include NPN germanium transistors, addition of a tone stack, true negative ground for complete compatibility with modern guitar equipment and other pedals.

https://www.youtube.com/watch?v=nLEuSNM_sos


Part I
Part one is an introduction to the purpose of this tutorial and will take you through preparing the aluminum chassis and transferring the artwork.  Some key highlights:
• My goal is to make labs in our curriculum fun and informative.  If you’re not having fun, you’re not learning!
• All documentation is available for students in the curriculum.
• The schematics and parts list are provided in the last video.
• Don’t be afraid to experiment!  How do you think I came up with this stuff??

Part 2
Part two is a tutorial on touching up the transfer on the chassis through the etching process.  Most of my students will focus on this part of the video because it is applicable to a myriad of other projects that have been dreamed up!  Some key highlights:
• Don’t etch unless you’re absolutely sure that the design is what you want.  You’re near the point of “know-return” (pun intended – sorry you Kansas fans).
• When you’re ready to etch, be sure to have PPE like gloves and goggles. 
• Dispose of your used etchant responsibly.
• Don’t over etch – the outcome will be blurry.
• Be sure to thoroughly clean the enclosure after etching.

Part 3
Part three is a straightforward approach for drilling the enclosure.  Some key highlights:
• Be sure to layout the drill locations using a pencil.
• Center punch the drill locations so the bit doesn’t wander.
• You don’t need a drill press, a hand drill will do.
• The proper drill size is important, always pilot drill first for good results.

Part 4
Part four is assembly and initial testing.  Remember that this is not going to be a tutorial on soldering.  I am assuming that you know how to solder.  If not, there are many tutorials out there on this, or if you’re a student of mine – I’d be glad to give you some quick tips.  I have a couple of still shots of component placement that will be helpful if you want to follow my exact lead, but this is not really important.  I advise that you lay out your components in a logical fashion from input to output.  Looking at the video, you’ll notice that on the back side of the pad-per-hole perforated board, I keep lead lengths short, with almost no jumpers – I use the component leads for connections.  This minimizes the possibility of picking up unwanted noise etc.  Some key highlights:
• Pre-assemble before soldering!  This way you can assure that there will be no mechanical interference issues.
• Socket the transistors so that you can swap them easily.  This is important if you are using older germanium parts that may have tonal differences between components.
• Test, test, test!  I advise testing the design without the bypass switch on the bench to make sure you can easily fix things before they are buried in the enclosure!
• Once you’re happy with the design, tack solder the transistors to the socket on the top side – just one of the leads will do!  This way they won’t vibrate off and they can be easily removed in the future with one application of the iron.

Part 5
Part five is the final assembly of the pedal as well as testing.  If everything else has gone well, this is the most fun part of it all because you get to use your new pedal!  Some key highlights:
• Make sure you follow the template on the schematic for wiring the pots so that turning them clockwise or counter clockwise accomplishes what you expect!
• The use of the UV LED is optional, but I like it.
• The bypass switch is a 3PDT so that the pedal doesn’t drain battery when still plugged in. 
• Double check all clearances with cords plugged in before closing the chassis.
• Have fun, rock on!
 

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