By: Dominic Sciarrino | Stompbox Electronics | Last Updated: March 12th, 2026 Today, we’re peeling back the curtain on Passive RC Filters! With just one resistor and one capacitor, you can build a circuit that selectively filters specific frequencies from an audio signal. That circuit is a passive RC filter, and it is one of … Continue reading Circuit 6 of 48: The Passive RC Filter