Rocket Booster

Welcome to my new blog through which I will take you with me on my journey to create my first DIY guitar pedal.

My motivation was, to learn a bit about electronics. While I already have a good understanding of simple electronics and theoretically know what a transistor, capacitor or resistor does, I always felt totally lost, when it got practical or I tried to understand what these electronic components do in a schematic – especially if it is an audio schematic.

To overcome these shortcomings, I followed a tutorial I found on barbarach.com on how to build a clone of the LPB-1 pedal, a simple boost pedal, which works as a simple signal amplifier.

To make things more thorough, I wanted to make my custom etched PCB and electricity etched Aluminium housing.

Breadboard prototype

Before I started to design my PCB, I made a simple breadboard prototype:

PCB Layout

I then continued with DIYLC to create my first PCB layout:

After some hours shifting things in Adobe Illustrator I was able to give it an artistic touch.

Etching the PCB

The next step is to convert the virtual PCB Layout, which so far only exists as an electronically stored layout into a real solder board that you can touch with your own hands and which directs currents from one electronic device to another.

We need to create a mask which we apply on our solidly copper-plated board. Unmasked parts will then be etched away to let only the desired copper traces reside.

I therefore laser-printed the mask on high-gloss photo paper. To provide a thicker layer for better masking, I used a four-colour laser printer. In Illustrator I switched from RGB to CMYK colour mode and set all four colour channels to 100 %

Printing on photo paper. The layout should be mirrored.

switching to CMYK in Adobe Illustrator

Setting all four colour channels to 100 %

The print must then be cut out and placed face down on the blank copper board. The copper board should be cleaned using acetone before.

Using pressure while ironing is essential since it helps to transfer the toner from the paper to the PCB.

Finished transfer. It took a couple of tries and a toasted PCB. You can use Aceton to remove unsuccessful transfers. Alcohol does not work, so when making corrections with a permanent marker, these corrections can be safely removed with alcohol without affecting the toner.

Etching using sodium persulfate. Temperature is essential. I started at about 45 Degrees Celsius but after 15 minutes nothing happened. When increasing to over 60 Degrees the etching finished within less than 5 minutes. I used a water bath in which I placed the form with the etching solvent.

You can use acetone to remove the toner from the board.

Etching completed.

The case will get crowded.

You can hold it against light, to check for proper line separation. 

Drilling the Board

We need holes in the board to connect the electronic elements to the copper traces. I drilled them using my dremel and very tiny drills.

Drilled with a Dremel.

Soldering

Now the fun part begins: soldering the resistors, diodes, and capacitors in place. 

You start with the smallest devices, like resistors and diodes.

Drilling the Case

Finally, we need to drill holes into the box which will hold the circuit. 

Drilling the container is really easy.

Connecting Plugs and Potentiometer

For my first pedal, I was mentally overwhelmed to figure out, how to correctly place the potentiometer on the board. That's why I connected it using cables. This also resulted in a board that lay loosely inside the case.

To prevent shorts I covered the board in isolating tape. This wouldn't be needed, if the board would be held in place by a potentiometer soldered directly on the board.

I had to put the negative on the outside since the plugs aren't isolated.

There is no space for a Bypass knob or a battery.

As you can see, my pedal box is very crowded so I do not even have enough space to install a bypass knob. My fault was to use capacitors with a way too high voltage rating. You only need a voltage rating slightly higher than the 9 Volt you actually power the pedal with. This would have made the components a lot smaller.

But also, I took a way too small case. One step larger would have made things much easier.

GitHub Repo containing all relevant files.