Two of the things that vintage effects are missing is true bypass switching & power supply filtering. While board mounted switches may be hard to change out, filtering the power is not? This simple circuit combines Reverse polarity protection & hum/noise filtering in very few parts, four to be exact. Here's how it works: The Diode (D1) protects the circuit from damage if the power is accidentally reversed. The Resistor (R1) filters out hiss from voltage, while The Capacitors (C1/C2) filter out hum from the voltage by pulling it through to ground. C1 filters out lower frequency hum & C2 filters higher frequency hum. All you have to do is install the circuit between the red battery wire where the voltage comes in and the voltage connection on the circuit board. The ground wire of the circuit can go to any ground point on the effect's circuit board or jack. That's it, it's that simple!!