Author Topic: Reusing old pedal parts  (Read 530 times)

R U Ben

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Reusing old pedal parts
« on: March 30, 2023, 02:21:48 PM »
New user here and still reading all the information on this cool project!

I can get cheap used multi-effect pedals from Boss/Zoom and was thinking that I could reuse some of it's parts.
For instance the enclosure, foot switches, expression pedal, plugs, maybe even some knobs, buttons and power supply...

The LCD's are usually 2x16 characters and would not work so one problem to solve  is to make the pi-Stomp LCD fit the enclosure.

What other problems do you see with this approach?

Thanks!

Randall (Admin)

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Re: Reusing old pedal parts
« Reply #1 on: April 01, 2023, 01:37:47 PM »
The enclosure is one of the trickiest design aspects of a multi-fx pedal IMO.  Especially if components piercing the top face and back face are attached to the same PCB.  There's almost zero chance that you'd find any existing enclosure that would have their holes align properly.

But, if you are willing to "fly-wire" certain things, like the input/output/power jacks, then yeah, you could mount the PCB with its encoder and volume pot to the top face, mill out a rectangle (or enlarge an existing) for the LCD, then attach the jacks to the back face via wires.  You could likely reuse jack holes that are already there.

A Boss MD-500 for example, might be a perfect candidate since it's deep enough (a pi-Stomp Core sandwich is 1.6"), and has a similar overall layout as the typical pi-Stomp layout.

As far as reusing switches, pots, etc.  Yeah, footswitches maybe.  They just need to be momentary type (preferably normally open, otherwise you'll need to do a software mod).  Pots you could use as tweak pots.  I would not suggest re-purposing an encoder.  Power supply won't likely be a low noise 5v/2A+ that is required.

R U Ben

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Re: Reusing old pedal parts
« Reply #2 on: April 04, 2023, 06:22:07 AM »
Hi Randall, thank you for your reply.

I cannot get a cheap MD-500 but I can buy a used GT-3 for 50€-60€ in working condition. It has 7 foot switches, expression pedal, 20 switches and a rotary encoder. It seems to have enough space around the LCD to enlarge it.

Meanwhile I managed to find the GT-3 Service Manual that includes full schematics and that gave me a crazy ideia:  swap the included CPU and DSP for the Raspberry by cutting pcb tracks and soldering wires to the RPi where necessary. The GT-3 uses 5V so a level shifter to 3.3V would be necessary. I suppose the driver for the codec (AK4522) would have to be written. The process is probably harder than it seems and not worth the trouble but I think it's possible.

A simpler option might be to just use the analog circuitry (buffer, volume pot) and feed it to the IQaudIO but even that is probably not worth the effort.

Anyway, reusing the GT-3's enclosure, footswitches and expression pedal seem to be a good option for the price.