I recently started to experiment with a different approach to pedal circuit building influenced by some of the techniques used by Fender back in the day. This approach uses fibreglass board, PCB eyelets and point-to-point component layout to create something that works great and harkens back to classics of days gone by.
My approach to these builds was with experimentation in mind. I wanted to try something new (as opposed to copying a ready-made veroboard layout) and I wanted to force myself to read, and more importantly understand, a schematic. This seemed to be a great way to do that while also being fairly cost effective.
Here's how I went about it…
Equipment & materials used
- Plenty of paper & a roll of sticky tape
- G10 FR4 fibreglass board (1.5mm thickness)
- Sharp, sturdy Stanley knife
- M2.5x3 through hole PCB rivets/eyelets
- 2.5mm drill bit
- 1.6mm, 2.4mm and 3.2mm centre punches
Step 1. Selecting a circuit
I picked a couple of different schematics first my first batch of pedals - a silicon Fuzz Face and a Lovepedal Champ. Both are relatively simple and follow some fairly typical approaches in terms of how they work. This page will guide you through the process of creating the Lovepedal champ as it's:
- Simple to understand with a small number of affordable parts
- Very similar in layout to loads of other boost and overdrive circuits
- Small enough to fit easily in a 1590B enclosure (you might even get it to fit in a 1590A with a bit of trimming)
This is the schematic that I picked:
The schematic is pretty much as I found it except I increased the power filtering cap to 100µF and removed the indicator LED as I handle this offboard.
Step 2. Creating the layout
This was definetly the most difficult part of the process but will probably come easier to anyone with PCB layout experience. Over multiple iterations I began to re-draw the schematic with a focus on the connections between the components - 47nF capacitor connects to input and to the base of the 2n5088 transistor, input connects to 1M resistor which connects to ground, etc.
Each time I re-drew the layout I double checked each connection against the schematic, reducing the number of connections and therefore rivets, and pulling everything tighter together to create a neat and space-efficient layout.
One final check of the layout against the schematic, by tracing each of the routes through the schematic and matching them to the routes through my layout, and I was ready to go.
Step 3. Creating a scale template
The layout I had created allowed for a board mounted pot so I started with this as the basis for my final, scale layout marking a hole for each leg.
Each component was measured against the drawing to make sure it would fit and the holes were gradually marked out until everything was translated from the layout sketch into the neat, 100% scale template.
Once the template was drawn I measured the size of board I would need and cut a couple of pieces to the right size. You can do this with a coping saw but I used a sharp knife - scoring the lines to about half of the the thickness before gently snapping the board.
Step 4. Drilling the boards
With the template drawn and the boards cut I taped it all together to keep everything straight and grabbed my trusty hand drill with a 2.5mm drill bit.
Obviously, if you use different sized rivets you'll just need to make sure you drill the correct size holes.
I carefully drilled each rivet hole until both boards were fully drilled.
Every now and then I'd grab a component or two (especially the potentiometer) and I'd make sure everything fit as expected. With the tape peeled off and a quick rinse under some running water I had two boards ready for rivets.
Step 5. Adding the rivets / eyelets
Working through the holes one at a time I push a rivet into the hole from the side that will hold the components. Carefully turning the board over onto a flat surface, without the rivet from falling out, I hold it all in place and get ready to fix the rivet.
First using the 2.4mm centre punch I give the rivet a couple of gentle taps. This starts to bend the end of the rivet over, trapping it in place. Next I use the 3.2mm punch and give it a couple more taps before finally giving it a tap or two with the hammer get a nice, flush finish.
While time consuming, I found that bypassing the smaller centre punch and going straight in with the larger one caused the rivets to split so would recommend taking your time and going steady. Or better still use a rivet setting tool and a drill press!
Step 6. Populating the board
Working on a hole at a time I begin to popluate the components on the board. For instance, our ground hole requires the grund lead, the negative end of the power filter capacitor, one end of the 1M anti-pop resistor and a link wire (made from a trimmed component lead from an earlier build). I pop all of these things through the hole and solder them in place.
I then move onto the next hole and work my way across the board until everything is in place. As you'd expect, some of the holes are a little trickier than others and I actually ended up soldering the 2.2M resistor to the back of the board to give a neater finish.
Turning the board over I popped the legs of the potentiometer (with a bit of insulating tape on the back of the pot) through their holes and soldered them in place.
Step 7. Finihsing touches
Finally I wire the board into my little test box and give it a test. First I check (using the short-circuit detection on my power supply) that there are no problem connections and then I switch the amp on to test with a guitar. With all volume controls at zero I slowly sneak them up and, when I can confirm the pedal is working correctly, I turn it up a bit and enjoy the fruits of my labour!
Now that I've got some of the techniques under my belt I will be returning to my Silicon Fuzz Face circuit with a big bag of assorted 2n5088 equivalent tin-can transistors. Wish me luck!
This layout extends the class Dallas Arbiter Silicon Fuzz Face circuit with a power filter cap, anti-pop resistor on the input and a wide-range input tone control.
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