Modern pedals, especially the “boutique” ones, often employ relay-based true bypass circuits to replace 3PDTs footswitches with momentary SPSTs. SPSTs are usually cheaper and more durable, due to their non-latching nature. Read more...

In guitar pedals, photo-MOSFETs are commonly used to mute signals coming out of effects circuits — either by disconnecting the circuit in an Optical True Bypass, or by temporarily grounding the output signal in a Relay True Bypass while switching. Read more...

To protect an effects circuit against reverse polarity there are two common options: a diode is either wired in series or it’s wired in parallel. This post is about series diodes. Read more...

Most guitar pedals require DC voltage to operate. If not using a battery, a power adapter will convert AC from a mains supply to DC. The DC output of an adapter is not perfect and there will often be a small AC component in the signal. Read more...

A voltage divider is a passive circuit producing an output voltage that’s a fraction of the input voltage. In guitar pedals they’re often used to adjust signal levels or bias active components like transistors and op-amps. Read more...

Guitar pedal circuits usually have two capacitors sitting on the signal input and output — so-called DC-blocking (or coupling) capacitors. These caps prevent direct current (DC) from entering or leaving the circuit, allowing only the guitar signal (AC) to pass through. Read more...

A guitar signal is alternating current (AC) but the vast majority of effects pedals require direct current (DC) to operate. So how do they work together in a pedal? Read more...

There are two types of current: direct (DC) and alternating (AC). In stompboxes (at least the ones that aren’t purely passive) you usually have both: DC from a battery or a power adapter and AC from your guitar’s pickups. Read more...

Older vintage pedals can often color the tone of a guitar even when they’re turned off. This is usually referred to as “tone sucking” — due to the loss of high frequencies and overall volume — and is caused by the so-called Hardwire Bypass. Read more...

Switches are generally named after the number of poles and throws. The leading letter (or digit) stands for the number of poles, the third letter for the number of throws. Read more...

Most guitar cables carry a monophonic (single-channel) signal. Their “TS” connectors have two contact points separated by an insulator band: tip (T) and sleeve (S). The audio signal travels over the tip while the sleeve is grounded. Read more...