Echo Play (PedalPCB Hydra Delay w/ Mods)
Overview
The "Echo Play" is my build of the PedalPCB Hydra Delay. This is a 4-head tape echo delay based on the Spin FV-1 chip. Can be compared to Catalinbread Echorec or Dawner Prince Boonar. Built in a 125B enclosure with top-mounted jacks.
It features JST connectors for easy disassembly, Lumberg jacks (audio, DC), and a custom decal.
It has several mods compared to the stock Hydra Delay build:
- Adjustable delay time range using the FV-1 clock module
- Mix knob uses 10kA (log) instead of 10kB (linear) for more usability, as per this post.
- Relay-based switching w/ remote control via MIDI using the Oscillator Devices Imp-3PDT.
Build notes
- First time SMD soldering for the FV-1 chip. I followed this step-by-step tutorial.
- Definitely recommend the Clock module! It's inexpensive and can be used to tune the delay time range. I use it to define what value the "noon" position is.
- All connections to/from the main PCB use JST-XH connectors to make disassembly possible and easier. Easier if you use pre-crimped wires. Some hard-soldered wires remaining as the the Imp pin spacing is not standard 2.54mm.
- I built a first iteration in Oct 2023. It had a "momentary oscillation" mod on a footswitch (short pins 1 and 3 of the Swell pot), and sub-par drilling. The second iteration was done in Aug 2024. I moved the circuit to a beige enclosure ; did better on the drilling ; used prettier black aluminum knobs and a beautiful green LED ("transparent diffused" LED from RetroAmplis) ; added the custom decal ; dropped the oscillation footswitch (didn't use it) ; cleaned the PCB with isopropyl alcohol for a cleaner and more durable result -- a best practice I'll apply from now on ; replaced the 3PDT with the MIDI switching module.
- Decal was designed in Inkscape and printed on a laser jet transparent shipping label sheet, as per Pougnet Pedals' technique, finished with two layers of clear coat.
- Inkscape drawing was invaluable to fit all the components inside the 125B box. The clock module sits on top of the SPST where the Imp-3PDT is soldered, with little clearance from the main PCB.
Cost of materials
| Part | Price (approx) | Vendor |
|---|---|---|
| 1x Hydra Delay kit | 65€ | Musikding.de |
| 1x Clock module kit | 4€ | - |
| 1x 125B Enclosure | 10€ | RetroAmplis |
| Lumberg jacks (2x KLBM-3, 1x NEB/J21C), green LED | 7€ | - |
| 5x black aluminum knobs | 8€ | Banzai Music (SKU 60084) |
| Imp-3PDT, 3.5mm TRS socket, SPST footswitch | 35€ | Oscillator Devices |
| Shipping fees | 15€ | |
| TOTAL | ~ 140€ |
Pictures
Downloads
- Inkscape drawing (includes a drilling template)
License
Drawings and schematics released under CC BY-SA 4.0.