This is a true-bypass relay bypass kit for your DIY pedals. It has loads of features:
- Soft touch SPST foot switches are easier to use, less expensive, and more reliable than traditional latching 3PDT foot switches. You can even use buttons, temporary toggles, or any other momentary activator.
- True bypass with a relay
- Hold to temporarily engage the effect when bypassed, or to temporarily bypass when engaged. Or Quick tap to toggle.
- Remembers whether your effect is bypassed or engaged, and next time you power up the pedal it will recall this setting. You can change to auto-on or auto-off by holding the switch while powering on.
- Uses smart wear leveling to ensure the EEPROM stays in good health forever
- Tiny size fits easily in a 1590A enclosure, or any nook and cranny you have
- Optional optocoupler muting can be enabled with a switch or jumper to mute any popping your circuit might exhibit while switching (not usually necessary)
This is optimized for true bypass in guitar effects pedals. For general-purpose switching, see our other digital relay module.
Custom behavior is usually possible. Get in touch with your ideas. Or if you just need to use a normally closed foot switch instead of the default normally-open, leave a note at checkout.
Kit includes everything you need except the foot switch (normally-open, SPST):
- PCB (20x23mm) with pre-soldered SMD regulator and other components
- Pre-programmed microcontroller
Build docs here: https://mas-effects.com/relay.pdf
Updated firmware: This will be shipped with an updated version of the firmware with an additional feature: By default it will remember the state of your pedal (bypass or engaged), and it uses a "wear leveling" technique to write to each EEPROM location as few times as possible to ensure it keeps working forever.
Holding the foot switch while powering it up will toggle between auto-on (3 LED blinks), auto-off (4 blinks), and memory (5 blinks).
The TLP222G optocoupler is optional, and mutes the signal briefly while switching. However we're no longer carrying it because
1. It's rarely needed. It's meant as a last resort for people whose audio circuit has a popping noise when switching (unrelated to the relay, and it happens with a regular switch too), however that's not terribly common with most circuits. When it does happen, it's usually better and easier to fix the root cause of a pop than get the duration and timing of this muting behavior working correctly. You have a balancing act between suppressing the pop but AVOID a perceived delay in switching.
2. The part has been discontinued. We'll need to redesign the board to work with an alternate part, but it's not worthwhile because of (1) above.
HOWEVER... if you want to source your own optocoupler, click the "Enable optocoupler code" option otherwise your firmware will not utilize it. By default it's disabled because it necessarily introduces a delay into the switching, which most people don't need or want.