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EarthQuaker Devices Night Wire Harmonic Tremolo
This isn't your father's tremolo - heck, this isn't even your father's harmonic tremolo!

by Phil O'Keefe

You're probably wondering how a "harmonic" tremolo differs from an ordinary tremolo. Good question - after all, tremolo can be created in a variety of different ways, but the main characteristic of traditional tremolos is amplitude modulation; they create cyclic variations in loudness or volume. A harmonic tremolo can create sounds that get louder and softer like standard tremolos, but they also have other characteristics that set them apart.

Fender used a harmonic tremolo circuit in some of their vintage amps; certain "blonde" and "brown" tolex era amps like the Bandmaster, Pro and Showman had a harmonic tremolo instead of the much more common bias or opto tremolos. However, they used relatively complex and expensive circuits that didn't stay in the lineup for long. While their sound is legendary, many people have never had the opportunity to hear one of those vintage amps. Well, now the good folks at EarthQuaker Devices in polymer-paved Akron Ohio have released their own take on this classic effect.

What You Need To Know

  • First, the look - the Night Wire has a really cool finish, with a black base with deep purple sparkles. The white graphics are silkscreened on top of that, with the lettering the same dark color as the base finish, so the contrast is good. The knobs are black with white pointers, making them easy to see too.

  • The Night Wire, like all harmonic tremolos, splits the signal in two using a high pass filter, and a low pass filter. These are modulated by a Low Frequency Oscillator (LFO) that is split 180 degrees. This allows the highs to be "moving" one way while the low frequencies are moving the opposite way, giving a far more complex sound than the up / down volume fluctuations of other tremolos.

  • The Night Wire has some tricks that allows it to do things that most harmonic tremolos can't, but in order to explain, let's take a look at the controls and what they do. First, consider the two toggle switches because they influence how some of the other controls behave.

  • The Rate toggle switch has two settings - Attack and Manual. When set to Manual, the rate of the tremolo is controlled by the setting of the Rate knob as you'll find on most tremolos. When set to Attack the rate of the tremolo is controlled by the strength of your pick attack, and the Rate knob becomes a sensitivity control for the dynamic tremolo. Playing harder results in a faster tremolo, while softer picking provides a slower speed.  

  • The Frequency toggle switch has three settings that affect the center frequency of the filter. In the LFO mode the frequency is continually swept by a LFO, and the speed of the LFO is set with the Frequency knob. In the Manual setting the Frequency knob determines the actual Frequency for the filter, while the Attack setting allows the center frequency of the filter to be controlled by your playing dynamics and pick attack. In this setting, the Frequency knob acts as a sensitivity control.

  • The Level knob sets the pedal's output level. With unity gain near noon on the knob, you won't have to worry about the effect not having enough volume to match your bypassed signal.

  • The Depth knob sets the strength or depth of the tremolo. Turning this knob down all the way bypasses the amplitude modulation, so the Night Wire will function as a envelope-controlled filter, fixed filter, or phaser; which one you get will depend on the position of the Frequency toggle switch.

  • The Rate knob's function does depend on the toggle switch settings. Again, when you select Manual on the Rate toggle the Rate knob acts like a Speed control for the tremolo, and turning it up will give you a faster tremolo effect. With the switch in the Attack setting this knob functions as a sensitivity control for the dynamic tremolo, with higher settings of the knob and harder picking resulting in a higher speed.

  • Unlike most harmonic tremolos, the center point of the two filters can be user-adjusted with the Night Wire. This leads to all sorts of interesting sonic possibilities. The Frequency knob and its associated toggle switch are the key to this. With the switch in the Manual setting the Frequency knob sets the center frequency for the high and low pass filters; turning it up selects higher frequencies while turning it down dials up a lower frequency. In the LFO switch setting the knob sets the rate of the LFO, while in the Attack setting the Frequency knob sets the envelope's sensitivity.

  • The excellent build quality is typical of other EQD pedals I've examined, with high-quality, full-sized parts mounted through-hole. Soldering and the (minimal) wiring are both neat and clean.  

  • Switching on the Night Wire is true bypass, but it uses a relay so the pedal will not pass audio without power. A bright white LED on the top panel next to the footswitch illuminates when the effect is active.

  • Speaking of power, the Night Wire has a 9V DC 2.1 mm center-negative ("Boss-style") power jack mounted on the top of the pedal, in between the 1/4" input and output jacks. Current draw is 78 mA. No adapter is included.

  • There is no internal battery clip, and battery powering is not supported.

  • The Night Wire measures 4.625" L x 2.5" W x 2.25" H, including the knobs.


  • It is a mono-only pedal. A stereo version of this pedal would be wickedly awesome.


This is far from your ordinary tremolo pedal. While it can give you some basic amplitude pulsations like a "normal" tremolo, it can create sounds that go way beyond that. The Night Wire creates multiple types of effects; it's part tremolo, part phase shifter / vibe, part filter and autowah and just a heck of a lot of fun! If you like the sound of a good tremolo but want something a bit different that exceeds the capabilities of your garden variety two- or three-knob unit, it's an excellent pedal to try out. The Night Wire can create sounds that are much more complex and lush than mere amplitude modulation, and at times it sounds like more than one effect at a time. Dynamic, hypnotic, and strangely sonically beautiful, it's a must-try pedal for not only fans of tremolo, but for all modulation lovers and effects fans.  -HC-


Questions? Comments? Want to share your thoughts about the Night Wire? Then be sure to check out this thread in the Effects Forum right here on Harmony Central!



EarthQuaker Devices Night Wire Harmonic Tremolo ($195.00 MSRP)

EarthQuaker Devices product web page, with audio examples    

You can purchase the EarthQuaker Devices Night Wire Harmonic Tremolo from:


Guitar Center    

Musician's Friend 


Sam Ash   



Phil O'Keefe is a multi-instrumentalist, recording engineer / producer and the Senior Editor of Harmony Central. He has engineered, produced and performed on countless recording sessions in a diverse range of styles, with artists such as Alien Ant Farm, Jules Day, Voodoo Glow Skulls, John McGill, Michael Knott and Alexa's Wish. He is a former featured monthly columnist for EQ magazine, and his articles and product reviews have also appeared in Keyboard, Electronic Musician and Guitar Player magazines.  

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