Most guitarists out there know about the tremolo effect. It’s the classic, swirly and surf-like sound that has been popular since the early 1950s. What many guitarists don’t know is that there are many different types of tremolos present in both amplifiers and pedals.
Understanding the different types, how they work, and what exactly they sound like, can help you to pinpoint the specific sound that you have in mind.
Luckily, we’ve created a little guide for you where we will cover the different types of tremolos and how they can have an impact on your sound.
Break out the Dick Dale, and let’s dig in.
VCA Circuit Tremolos
VCA Tremolos help to affect the input signal of a guitar (or any instrument for that matter) by providing a variation in volume. They’re pretty versatile overall.
You can create anything from a smooth, pulsing tremolo to a fast, helicopter-like tremolo to the likes of Tom Morello.
VCA Circuit Tremolos also give you a fair amount of control. Some common controls that you’ll find on these types of tremolos are frequency, depth, and rate, helping to control the kind of sound, the amount of the effect, and the output.
VCA tremolos can differ quite heavily regarding sound depending on the type of wave that they use. Let’s talk about the different types of waves that you can select from to see what they do.
Triangle Wave Tremolos
If you’re looking at guitar pedal tremolos, you’ll most likely find yourself a triangle-wave tremolo. These types of tremolos are the kind you’re also likely used to hearing, as they’re found in bigger Fender amplifiers. Next time you plug into a Fender Twin, crank up the tremolo depth. That’s a triangle wave!
Triangles are unique in that they have an even rise and slope, providing the most linear type of tremolo, perfect for getting that “in-tempo” effect.
One of our favorite triangle wave tremolo pedals on the market has to be the Fulltone Supa-Trem ST-1. It has a warm, clear, and even tone, similar to that of a Fender Twin.
Square Wave Tremolos
If you’re looking for that more-than-obvious choppy sound, the square wave tremolo is one of the best around.
Because of the wave shape, you get extreme volume dips that give you a helicopter-like sound. Square wave tremolos can play in the same linear fashion as triangle wave tremolos, though they give you the ability to push your signal to greater extremes, almost creating an on-off kind of sound.
Check out the video below to see a square wave in action. Click to around 2:30 and listen to how the volume cuts in and out like a knife.
Sine Wave Tremolos
Sine Wave Tremolos act as a great transition to our next section, as they were originally found in a variety of different amplifiers. If you’ve ever heard a softer, pulsing tremolo played with an amplifier, it’s most likely a sine wave.
That’s because sine wave tremolos are the most subtle of all. While they don’t work in a linear fashion that is nearly as accurate as triangle or square waves, they can create impressive, psychedelic effects that almost give your music a raw, rushed or swung feel.
Check out the sultry sounds of one of our favorite sine wave tremolos on the market: The Moody Sounds Tremolo.
Vintage Amplifier LFO Tremolo
So now you’re aware of the awesome tremolo effects that are produced by pushing waveforms through a VCA circuit, though many different tones came long before that was possible.
When we listen back to vintage amplifier tremolo circuits of the ‘50s and ‘60s, we hear some incredibly unique characteristics thanks to the way the sounds were produced.
These vintage amplifiers used what we call LFO circuitry.
LFO modulation is used alongside a variety of capacitors and resistors to help produce a non-fixed rate tremolo effect. The three different types of tremolo use LFO as a building block of their sounds, though they each have a flair unique to themselves. Let’s see what they’re all about.
Okay, so while harmonic tremolos aren’t necessarily pure tremolo effects, they do still change the depth and amplitude of the signal while providing something a little special.
The difference between harmonic tremolos and other tremolos is that they split the lower and higher frequencies in half to modulate them separately. So while you still get the tremolo effect, you also get an interesting, phase-like sound too.
It was actually one of the very first effects to ever be built into vintage amplifiers thanks to Fender. Check out the Brown Face Tremolo for an example of the this sweet, harmonic tremolo sound (around the 2:50 mark).
Power Tube Tremolos
Power Tube Tremolos came along after harmonic tremolos, as they were less costly to produce thanks to the removal of a few of the working tubes. Instead of using a two-phase LFO like the harmonic tremolo, it used a single LFO to impact the bias of the power tube right before coming out of the amplifier.
When you ran your guitar signal through an amplifier with power tube tremolo, your signal was split so that one tube would take in the positive side and one tube would take in the negative side. They would then be added together at the output stage, giving you alternating gain thanks to the push and pull of the current running through the tubes.
The uniqueness of power tube tremolos comes from the harmonic distortion. Essentially, when the signal reached a maximum level, the tubes distorted, leaving a beautiful and dynamic saturation effect that was relative to the power tube bias. Check out the Carl’s Custom Amps Blonde CPC-20 Demo Below for an example of this gorgeous tremolo:
Photocell Tremolos use what we know as an LDR (Light-Dependent Resistor) and a small light bulb paired with an LFO. The bulb works by getting brighter and dimmer to help create resistance and acceptance of the LDR. That resistance is read by different circuit impedances within the tremolo to create a change in the signal level.
This was one of the earliest tremolos that provided a choppier sound, similar to that of a square wave, as the light fluctuated quickly, creating an on-and-off movement.
For sweet, magical chop that came before the advent of VCAs, a photocell tremolo was your best bet. The same goes if you’re looking to get a hold of that classic surf and country sound.
Other Types of Tremolos
Phase Shift Tremolos
If you listen back to the old Magnatone amplifiers of the 1950s, you’ll hear what is known as a phase-shift tremolo. They sound very similar to sine-wave signals, though they give you a warmer and more adventurous blend of modulation that almost gives you bell-like phase.
Magnatone actually pinned this sound as a vibrato effect, though the audible changes in amplitude tell you that it is a tremolo, even with that unmistakable vintage warble. Looking for the sounds of the Delta Blues? Check out this vintage 1955 Magnatone below:
Now That We’ve Gone In Depth…
Excuse the horrible pun, but aren’t you happy that you know pretty much everything you need to know about the wonderful world of tremolo. You’re one step closer to building your own pedal!
Tremolo effects may not seem so complex on the outside, though when you look deep and listen to the different kinds, you’ll begin to understand what makes them so unique.
Get out there and try them all!
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