The 6 Types of Tremolo Explained

For an effect as seemingly simple as tremolo, players face a nearly overwhelming array of options. True, many of today’s simple tremolo pedals hearken back to the transistor-based Schaller and EA tremolo circuits from the late ‘60s, but the story doesn’t end there.

The Toneczar Powerglide and Fulltone Supa-Trem use a photocell system like those of the classic blackface and silverface Fender amps. Tube-based tremolo pedals, like the Kingsley Bard, offer an authentic bias-vary tremolo.

With the recent resurgence of digital pedals, even more options come into play — the Strymon Flint, for example, digitally processes the signal and gives a myriad of classic tones in one box. Others, like the Diamond and Empress tremolos, feature an all-analog signal paths controlled via a digital nerve center.

What that means to the buyer is that essentially any tremolo sound and function imaginable is available. Knowing the differences can help players choose the perfectly pulsing stompbox.

Triangle-Wave Tremolos

The triangle waveform, likely the most pedal-ized form of tremolo, is typically found on the larger Fender amplifiers like the Twins, Deluxes and Supers. Its photocell-derived waveform rises and falls in a clear and linear fashion. The slopes are direct and precise and, even when played slowly, the peaks and valleys poke prominently through the signal.

“Crimson and Clover,” perhaps the most famous example of recorded tremolo, perfectly captures the logical pulse of triangle wave — it’s smooth and velvety, but it slices the signal in a musical way. Some examples of tremolo pedals that use a triangle waveform include the Boss TR-2, the Demeter Tremulator, the T-Rex Tremster, the Dr. Scientist Tremolessence and the Fulltone Supa-Trem.

Sine-Wave Tremolos

Unlike the triangle-wave, the sine-wave tremolo usually results from the modulation of a transistor or a power tube, almost like overdrive. It was originally found on small combo amps from the ‘50s. That simpler, less-precise tremolo works by gradually adding and decreasing power, which results in a smooth, sometimes asymmetrical, undulation.

Sine-wave tremolo is often the first choice for subtle tremolo. At more extreme settings, sine wave is described as swampy and syrupy, and it can almost begin to take on the feel of a square-wave tremolo. Sine-wave tremolo pedals include the Basic Audio Throbby, the Mad Professor Mellow Yellow Tremolo, the Kingsley Bard, the Malekko Omnicron Trem and the Monster Effects Swamp Thang.

Square-Wave Tremolos

For a truly overt effect, look to the square-wave. Originating from the Vox Repeater, the square-wave is a pronounced waveform that, at extreme settings, can result in a totally on-off pattern.

That square-wave is prominently displayed in pedals such as the Catalinbread Valcoder, the Earthquaker Devices Hummingbird and the Flickinger Vicious Cricket. Many of them feature the square-wave as a secondary option.

Phase-Shift Tremolos

Phase-shift tremolos take their inspiration from the large brownface Fender and Magnatone amplifiers. Besides the sine-like rise and fall, a slight phase-like quality imbues the signal, resulting in lush, complex modulation.

The Effectrode Delta-Trem and the Fuchs Crem de la Trem are roundly praised contenders in that category, as is the Bearfoot Mint Green Mini Vibe, which takes its inspiration from the oscillating warble of an electric organ.

Specialized Tremolo Tremolos

With so many solid entries in the traditional tremolo market, it seems that manufacturers are looking for compelling ways to push the field forward. Bias adjusters, filters, tap tempo, stereo-panning and expression pedals have all added amazing functions and opened up new types of sounds.

Even some ring modulators can, at slow settings, become tremolos while crazed pedals like the Lightfoot Labs Goatkeeper treat tremolo less as an effect and more as a pattern creator. Other bleeding-edge tremolo pedals include the diy Tremulus Lune, the Electro Harmonix Super Pulsar, the Spaceman Voyager, the Chase Bliss Gravitas, the ZVex Seek Trem and Sonar, and the Cusack Tap-a-Whirl.

Volume Boost Tremolos

The basic principal of tremolo is that the volume of the signal is altered in a rhythmic, musical way by cutting volume and then adding volume back in. Thus, the signal can only be as loud as unity when the tremolo’s wave has peaked — so, only a fraction of the time.

Most tremolos now feature some sort of boost system that allows the user to increase the overall volume of the signal when the tremolo is engaged. Thanks to that, tremolo no longer needs to result in a perceived drop in volume. By boosting the overall signal, the affected signal can now comfortably match, or even exceed, unity.

Far from a merely a static effect, tremolo can exhibit nearly limitless personalities and functionality. Have fun exploring!