Free Guitar Pedal Circuit Calculators
GuitarPedalCourse.com mini-appsInteractive teaching tools for guitar pedal builders. Drag real component values, type your own, and watch the frequency response move. Every calculator plots the exact curve next to the nearest-E12 build, so you know what the parts in your drawer will actually do before you solder anything.
RC Filter Calculator: High-Pass and Low-Pass
The building block of every guitar tone circuit: one resistor, one capacitor, and the cutoff frequency fc = 1/(2πRC). Set both filter types, see exactly where the rolloff starts, and learn why coupling caps cut bass and tone caps cut treble.
Open calculator → EQGyrator Bandpass Calculator
An op-amp pretending to be an inductor: the gyrator circuit behind countless EQ pedals and amp voicings. Tune the center frequency and bandwidth with real part values and watch the band move across the guitar's range.
Open calculator → Tone ControlBridged-T Passive Mid Scoop
A bridged-T network with a depth pot in its shunt leg: it carves a low-mid notch while bass and treble pass untouched. Sweep the depth control and watch the midrange dip deepen and slide across the honk region.
Open calculator → Tone ControlGrounded-Wiper Mid Scoop
A second flavor of passive mid-scoop tone control: a bypassed series pair with the pot’s grounded wiper splitting two shunt legs. Resize the notch and see firsthand why what drives a passive tone network changes what it does.
Open calculator → Tone ControlBig Muff Bass & Treble Tone Control Calculator
The famous Big Muff tone section expanded into a two-knob version with separate bass and treble controls. Turn each pot independently and watch the two halves of the curve trade off, so you can see exactly how this passive stack shapes the whole spectrum at once.
Open calculator → Tone ControlTS/SD-1 Style Tone Control Calculator
The active one-knob tone stage inside the Tube Screamer and the Boss SD-1. Load either pedal's stock values with one click, toggle the SD-1's C5 feedback cap in and out, and watch how a single knob sweeps the response from dark to bright.
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Quick answers for pedal builders
What is an RC filter?
An RC filter is the simplest frequency filter in electronics: one resistor and one capacitor. Arranged one way it is a high-pass filter that removes bass; flipped, it is a low-pass filter that removes treble. Its cutoff frequency is fc = 1/(2πRC), and nearly every coupling cap and tone cap in a guitar pedal is really an RC filter in disguise.
What is a gyrator?
A gyrator is an op-amp circuit that simulates an inductor using a resistor and capacitor. Paired with another cap it forms a bandpass EQ section, which is how graphic EQ pedals and amp mid controls get inductor-style band shaping without the cost, size, and hum pickup of a real inductor.
What is a mid scoop tone control?
A mid scoop is a tone control that cuts a band in the midrange while leaving bass and treble close to full level, the shape behind many "smiley face" amp settings and heavy rhythm tones. Both scoop calculators here are passive, variable-depth versions built two different ways, so you can compare how the same sound is reached with different circuits.
Why do the calculators show a nearest-E12 build?
Real resistors and capacitors come in standard E12 values, so the exact number a formula asks for usually does not exist as a part you can buy. Each calculator plots your exact values as a solid curve and the nearest-E12 build as a dashed curve, which shows what off-the-shelf components will actually do to the response before you order or solder anything.
All calculators are free, run right in the page, and are built from derived transfer functions rather than approximations, the same math you’d use on the bench. More calculators are on the way as the collection grows.