A Brief History of Tremolo and Other Modulation Effect Pedals


The history of guitar pedals is a complicated mess of vocabulary. The same effect may be given a range of different names depending on the pedal maker’s whims. In this article we will be examining the origins a specific genre of effects known as Modulation or “Mod” effects.

Modulation effects are defined by their use of sonic qualities that change over time. This change over time can affect a wide range of factors such as: Volume (Tremolo), Pitch (Vibrato), Delay Time (Phaser and Chorus), as well as any other knob you might find on a guitar pedal. Many advanced pedals may even change multiple parameters at once! Modulation effects are generally known for their ability to add spaciousness and movement to any input signal.

Hello World!
The Birth of the World’s First Effect Pedals

Before automatic systems were invented, Tremolo relied on the skill of a musicians who could subtlety modulate their playing strength. Originating form 17thcentury string orchestras, the word “Tremolo” if derived from “Tremolando,” which means “shivering sound”.

DeArmond Trem Trol 800

Tremolo effects that automatically changed volume over time, were some of the very first effect pedals ever created, predating distortion pedals by more than a decade. The first tremolo pedal was the DeArmond Trem Trol 800 released in 1941. it was heavy, expensive, fragile, and impossible to use on stage. Despite these faults, it was widely adopted as a replacement for an even more cumbersome studio based effect that required careful measurement of ripples in giant tanks of water. The DeArmond Trem Trol 800 used a small tank of conductive fluid similar to Windex, which was wobbled by an electric motor. The wobbling conductive fluid strengthened and weakened the signal flowing through it, creating volume variation over time.

All in One
Amp Manufacturers Embrace Modulation Effects

By the 1950s the popularity of Tremolo and Reverb was growing, so many amp manufacturers began to incorporate effect circuits directly into their products. These build-in circuits were far more simplistic, utilizing a sine wave that modulated the bias of the amp’s pre-amp or power amp. This amp-based tremolo was limited to the sine shape, but had a desirable “fuzzy” tone caused by the gently varying distortion inherent in the design. By the 1960s, Fender’s amps shifted to more complicated photoresistor based circuit that allowed for more precise control, but unfortunately lacked the fuzzy sound of the previous Bias/Amp based circuits.

New Shapes
Introducing the Op-Amp

Near the end of 1960s, the invention of the operation-amplifier integrated circuit (Op-Amp for short) allowed for a wide variety of volume shapes such as triangular waves and square waves. Some pedals such MXR’s Tremolo could also morph between different volume shapes. Op-amp circuits were also more compact, allowing for stereo inputs and outputs within a single pedal.

Quick Control
Tap Tempo and Tremolo

One recent development is the introduction of Tap tempo control for tremolo speed. A company called Electric Druid created an effect circuit called the TAPLFO. This circuit digitally controls the speed of an amp/bias tremolo, providing the combination of features: precise control, flexibles volume shapes, and the fuzziness of older of amp/bias tremolo circuits. With the TAPLFO circuit, it is easy to dial in triplet and sixteenth note intervals. The first company to use this circuit was Chase Bliss Audio, extolling the motto: “Digital Brain, Analog Heart”.

Steady Evolution

Incremental improvements over the last 60 years have evolved cumbersome and fragile tremolo mechanisms into portable and durable effect pedals. Our team at Trinalog is looking forward to what comes next!