In January 2012, I started building a delay pedal called the Rebote Delay. It’s a pretty popular project among DIYers – it’s a digital delay based on the PT2399 IC, but it sounds like an analogue delay. Apparently it’s a flexible design, which makes it easy to modify and make changes to.
I ordered a pack of ten PT2399 chips from eBay, and after waiting weeks for them to arrive from Hong Kong, I made a start. The build was fairly straight forward, this was my 4th build and I’d started getting into a good routine:
- Research and find a verified layout (mostly on DIY Stomp Boxes, Free Stomp Boxes and Sabro Tone)
- Check to see if I have all the components, if not order some.
- Make the trace cuts in the vero
- Solder in the jumpers, IC sockets, transformer sockets, resistors, capacitors and off-board stuff (in that order)
- Prepare the enclosure with jacks, LED, footswitches and put it all together
I used this layout from Sabro Tone, and here it is all working, before I box it up:
I had to substitute a couple of parts because I didn’t have the right values, so:
- C9 became 4.7pF
- C23 became 56pF
- The 15kΩ resistor between Infinite 3 and Infinite 6 became 18kΩ
- The 11kΩ resistor between Infinate 1 and Infinite 4 became 10kΩ
- To make the delay times longer (and dirtier) I replaced the 50k pot for a A100k pot
The delay works great and sounds awesome (especially making crazy noises with the Infinite switch on!), but I though it would be cool to include a blinking light that flashed in time with the delay time, so that you have some indication of the speed of the delays – regardless of whether the effect is on or off. I looked around and found the add-on below. It’s an extra bit of circuitry that blinks a LED in time with the PT2399 – and it’s almost as big as the actual delay vero! It connects to Ground and Pin 5 of the PT2399, and then it just needs 5v, which you can get from Pin 1 of the PT2399. I used a BC548, because I didn’t have a BC549 with no problems.
Here’s a short video of it in action:
This add-on worked well, but I noticed that it introduced a little audible ‘click’ in time with the LED blinking, so it’s still in there, but it’s disconnected. One day I might make an ‘on-off’ switch for the blinking function.
Here is the finished product: