Introduction: DIY Guitar Effect
I've decided to build an electric guitar effect. There is plenty of schematics around the internet, along with the short videos showing how they work, so if anyone want to pick one - there is plenty to choose from.
I've decided to go with "Keeley electronics Mag Echo"
Step 1: Schematics and PCB
Schematics for this particular effect can be found In this document: https://www.pedalpcb.com/docs/MagnetronDelay.pdf
it also contains bill of materials.
Having schematic it is easy to design a PCB, though I decided to save some time and use already designed one, from this website: http://effectslayouts.blogspot.com/2019/11/keeley-mag-echo.html
In order to make PCB I've printed it on the chalk paper on the laser printer, and then transferred printout onto the PCB by laminating machine, this way of thermotransfer method gives a quite good results.
Once transferred, I've etched the PCB with B327 etchant (Na2S2O8). As with any other chemical usage, use caution while handling it.
After etching, there are holes that needs to be made for the elements, 1mm drill bit with small hobby drill does the job.
Populating PCB with electronic elements is a bit tedious job, and soldering require a bit of skill, but with some time practicing it becomes quite easy ;)
Some of the components are wired off the board, what sometimes makes them easy, and sometimes a royal PITA, but as they say "your mileage may vary"
Step 2: The Case of the Test Case.
For the case I've picked 1590B. Drilling layout can be also found at http://effectslayouts.blogspot.com/2019/11/keeley-mag-echo.html though I've decided to make my own design.
There is plenty of ways to decorate your box. And I have not picked the easiest one. I have etched design in the aluminium by Sodium Hydroxide (NaOH) that is a popular house hold chemical for unclogging drain pipes.
First I've tested the method on the backing plate. Design made in inkscape, printed on the laser paper, and this time transferred to the aluminium by iron. Once transferred to the plate, put it into water for paper to separate from the plate leaving toner on the aluminium And making it possible to etch.
Step 3: Test Etching of the Backplate
Sodium Hydroxide is more aggressive than B327 so please exercise caution. Dumping a piece of aluminum to the etchant will etch the exposed aluminium and leave the design.
Step 4: Etching the Box.
As with the backplate testing, Inkscape was used to make the design, but unlike the test design, this time, writing was involved, so make sure you'll mirror the design before transferring it to the aluminium. If you'll miss this step - use acetone to clean up box and transfer it again - correctly this time ;)
Step 5: Drilling
I've used drilling template from the same page that is hosting PCB transfer image, but modified it with Inkscape to my liking :) and drilling all required oppenings in the case.
Step 6: Painting the Box
I like the look of hammered case, so hammerite paint in nice green colour was my type, I have not got it in the spray can, so I had to use roller and brush, and it took me a couple of tries ;) but once painted, I've used 1500grit sand paper to rub off paint of the design exposing it from under the paint. And applied clear coat on it as final touch.
Step 7: Measure Twice, Cut Once
Just like that, always double check, because you'll end up like me ;) but cutting tools did their job, and fix my mishap.
Step 8: Put It All Together
Putting all together, 3PDT switch is being used.
Wiring schematic from this page: http://www.muzique.com/news/3pdt-switch-wiring/
I have still not decided on the potentiometer knobs, so for now, it'll be knobless ;))
Have fun with it.
Participated in the