What happens if power is removed while the pedal is engaged? Will the latching version switch back to bypass to allow signal through?
So I bought several of the latching version of these to try out, and I just finished using one to convert a Boss pedal to true bypass. Some observations:
1. If you remove power while the pedal is engaged, the pedal will remain switched "on," which means you won't be able to switch it back to bypass mode until power is reapplied. Until then it stays engaged, which means it won't allow signal through. If you need the pedal to switch to bypass mode when power is lost, the non-latching version should do that.
2. When power is reapplied, the pedal switches to bypassed mode, regardless of whether it was bypassed before it lost power. So if you lose power while the pedal is engaged, and then power comes back, the pedal will be bypassed.
3. Switching is surprisingly reliable. Debouncing is solid. I haven't been able to trip it up. Holding down the switch does NOT cause the relay to oscillate back and forth, like in some flip-flop driven circuits.
All in all, I'm very impressed with these. The fact that it doesn't require a microcontroller makes it friendlier to DIY than most other latching relay boards I've seen. In fact, this is the only non-microcontrolled latching relay board I'm even aware of. It's my new favorite module for converting Boss and Ibanez pedals to true bypass.