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Project Notes

#339 GuitarEffects/DelayKit

Build and test a PT2399-based delay pedal kit.

Here’s a quick hit to demo the delay unit, with a clean guitar signal and all the effects settings (mix, repeat, delay) on “11”..

Build

Notes

I have been reading up on the PT2399 echo audio processor, and a good way of seeing one action is to pick up one of the many delay effects pedals.

The kit I obtained is nicely put together with a pre-drilled and decorated 1590B enclosure, and some very nice knobs and smooth pots.

Unboxing

DelayKit_parts

DelayKit_instructions

DelayKit_pcb_front

DelayKit_pcb_rear

Assembly

Assembly was a breeze - the silkscreen on the PCB is clearly and completely marked, and the assembly instructions provided had the details on correctly wiring all the connectors and pots.

The only variation was two ceramic capacitors that were provided at slightly different values than printed on the PCB. The values must not be that critical as it works fine with the substitutions.

DelayKit_assembly1

It’s a tight squeeze, but all packs into the enclosure nicely. The PCB is the correct size so that the lip on the base of the case will prevent the board shorting on the case (obviously care required to ensure there are no protruding wires or over-sized solder joints).

DelayKit_assembly2

Assembly complete. The kit even included some nice rubber feet to stick on the bottom.

DelayKit_assembly3

Note that as is common for effects pedals, the 9V jack is centre-negative.

Build

Schematic

I think this is a reasonable transcription of the circuit. The use of the PT2399 is very similar to the echo circuit including in the datasheet.

Although the signals in and out are analog, the PT2399 appears to operate by digitally sampling and remixing with ADC and DAC and 44kb of internal memory.

Schematic

Credits and References

About LEAP#339 Guitar EffectsAudio
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This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.