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The Expanse: Behind the Back Plate
Step by step walkthrough of how The Expanse harmonic tremolo is built
This is a picture tour of what’s inside The Expanse and how it comes together. I had to cut out many pics due to size limits on these articles, so let me know in the comments or by replying if there’s anything I glossed over that you’d like to see in greater detail.
The Expanse has 3 PCBs (printed circuit boards):
Controller board - does the switching, “listens” for taps or long-presses on the foot switch and toggles the effect
Main board - does the audio effects
Jack board - input, output, and two expression jacks
The fabricator who creates these PCBs also does assembly for most of the parts, using pick-and-place machines. There are a few parts they don’t have on hand and with the relatively small quantities I produce, it makes more sense to simply source those parts and solder them on in house.
There has been an ongoing digital microcontroller shortage for a couple years now, and you basically have to take whatever you can find at any given time. So this board is a modular piece that can be easily redesigned to accommodate a variety of microcontrollers without impacting the rest of the pedal. If no microcontrollers are available at all, I even have a completely analog version we can swap in.
The main board does all the audio processing. Like the controller board, I get much of it pre-assembled. A few things I’ll solder in house:
Unfortunately I had to cut a lot of these pics for space savings, but you can guess how it came together.
You can also see here the addition of the DC power jack. Both the power jacks and the input/output/expression jacks are securely mounted on the panel. Many pedals these days use perpendicularly board-mounted jacks that subject the solder joints to considerable force every time you plug and unplug cables. Over time this leads to cracked solder joints and is by far the #1 source of broken pedals.
That’ll never happen with this pedal. It takes more time and costs a bit more, but it’s definitely worth it.
Putting it All Together
Wow that looks quick and easy when I paste a few pics like this… but it’s actually a VERY long build compared to most pedals. Arguably I have it priced way too low, but I’m going to hold it out as long as possible.
Anyhow, that’s all for now. Any more you’d like to see?
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