I’ll do the final schematic and bill of material, then do the soldering layout for a protoboard. I’ll plan out the enclosure, and finalize the enclosure. I’ll finally assemble it and do test and demo.
Trying out different things last time I thought the “original” sounded good so I went with that. I used BC109C transistors. They are high gain transistor, the ones I used were with beta around 520 (according to my meter which is not very accurate).
My son likes using batteries in his effects, I prefer using a pedalboard with power supply, so I decided to do both for this build. Without further ado – here’s the full schematic:
I’ve added a little ** next to 10K resistor. That’s current limiting resistor for the chosen LED. I chose a very bright low current blue LED. Common values you might see online like 1K or so would just blind me – I increased the value until the brightness was good for me.
When choosing LED and current limiting resistor you need to look out for how bright it is, what the current is etc. Or do as I did, just start with 1K and increase the value until you’re satisfied with the brightness 😉.
Wiring the Battery
Battery is wired so it is disconnected when either DC jack is plugged in, or the cable is not plugged into the input jack. This is to preserve battery since the effect is ON whether it’s in the signal path or not.
Bill of Material
Here’s the final list of components:
|Empty Guinness flavoured fudge tin box (very nice tasting fudge!)||Enclosure. I thought it was nice looking and the taste was just right 😋|
|Protoboard||1/4 breadboard size protoboard|
|Jumpers and wires||24 AWG solid core wire and 28 AWG stranded wire (24 AWG might be slightly easier to use)|
Anything thicker might be hard to stick into the protoboard.
|J3||Cliff FC681473||DC Power Socket|
|J1||Switchcraft 12||In – stereo Jack (I need stereo here for battery)|
|Out mono Jack (I used stereo, it’s fine, I just ran out of mono jacks)|
|1K linear pot* (9mm, panel mount, no bushing, D type shaft)|
|500K log pot (solder lugs, metal shaft and bushing)|
Alternative pot: Alpha RV16AF-10-15K-A500K-3 for example
|Knobs||This depends on what pots you use. I used D type shaft knobs. If using Alphas you’ll need knobs that fit 6.35mm straight shaft.|
|S1||SF17020F-0302-21R-L||Taiwan Alpha 3PDT latching foot switch|
|C1||2.2uF||Electrolytic cap 25V|
|C2||22uF||Electrolytic cap 25V|
|C3||10nF (0.01uF)||Metal film PET cap|
|C4||47uF||Electrolytic cap 25V|
|R1||330 ohm||1% 250mW metal film|
|R5||10K||LED current limiting resistor|
|D1||Led||3mm low current blue LED, 2.8-3.6V forward voltage (151034BS03000 Wurth electronic)|
|Q1, Q2||BC109C||Silicon Transistors|
I used a panel mount 9mm pot – I was ordering 1K linear pot a way back … the only ones I had left 😅. It’s OK, it works, it’s a pain to mount though, had to drill an extra hole to the protoboard to be able to mount it. Also, I could not use PCB support because of this choice, I had to screw the board onto the box.
Here are all of the components before I started assembling them:
Board Layout Plan
As usual, I prepared one possible layout with DIY Layout Creator:
Here’s the diy file for opening in the program:
Just a note on those wires that seemingly are not connected to anywhere. Purple VOL wire connects pin 3 of the 500K log pot with the board. I just tend not to put all the wire connections fully into the diagram. The diagram goes a bit unwieldy. Here’s what I mean (this is what I ended up in the end):
The key is to connect wires with the same label together.
If you’re using 1K pot with soldering lugs instead of the panel mount I used, just wire it up like this:
I did usual enclosure planning in Inkscape:
The tin box is way bigger than Hammond 1590A enclosure so planning is not that critical. This did help me out with final placing of LED for example. Also – I totally forgot that box lid is deep, without this planning I would’ve probably had input/output jacks a bit higher which would’ve prevented me to close the box.
I’m just saying, it is better to plan up front, even if it’s not critical, saves some trouble later.
This enclosure is a bit different – it’s just a tin box. No artwork, the box looks nice on it’s own. However, working with tin is not as easy as working with aluminium (aluminum) box – at least I find it harder.
In principle, the drilling is the same – except the box material tends to tear a bit, especially when using bigger drills. It’s a bit awkward, and requires a good bit of filing to smooth out the edges a bit. I used a wooden block to support the sides when drilling, otherwise the tin gets ripped by the drill bit.
Anyway, here’s how the enclosure looks like:
I used the template I printed out, then used a punch hole tool to mark the holes. Notice the indentation on the wood block where I punched the holes – I had the wood block under the box to avoid too much deformation of the box. The final result does not look as clean as when drilling the “normal” box, but it is still fine.
I’m sure there are specialized tools for cutting these holes, but whatever, we got to use what we have, right?
I did soldering exactly how I planned it in the diagram above. Similarly like before – I soldered them based on height, from smallest (jumpers) to biggest (electrolytic caps, that pot that goes on the board and LED).
Here’s how it looks like, practically 1-to-1 with the diagram:
I had to drill a hole for mounting the pot first – it would’ve been very awkward if I did it with some components on. Then I did it as I said, based on height. Once the board was complete – it was testing time.
Once I confirmed the board is working – I went on to assemble the rest of the components – jacks, remaining pot, the battery snap.
It started to get messy with all the wires, but I just followed the diagram and finished the box. Due to the panel mount pot I had to screw on the board to the lid, otherwise I would’ve used PCB support feet, or something like that, to secure the PCB. Anyway, the end result looks good I think 😊.
The last thing to maybe think about is reinforcing the area around the stomp switch. The box feels surprisingly sturdy, but with time I’m sure it will cause the surrounding area to deform and break.
Final result is looking good:
Here’s how it sounds: