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Electro Harmonix Hot Wax Dual Overdrive
One pedal, two classic EHX overdrives, and an invitation to color outside the lines

by Phil O'Keefe

Have you ever wanted to color outside the lines? Some people consider that to be breaking all the rules, while other people think of it as a sign of creativity. If you fall into the later category and you're a musician, Electro Harmonix probably had you in mind when they designed their latest pedal - the Hot Wax Dual Overdrive - a pedal that attempts to mix a Crayon with Hot Tubes - it packs those two classic EHX pedals into one enclosure, and is designed to appeal to guitarists and bassists. The question is, does the combination of two overdrives result in useful musical colors you can drip all over your music, or does it just make a waxy sonic mess? Let's fire one up and see.

What You Need To Know

  • The Electro Harmonix Hot Wax combines two popular EHX overdrives into a single pedal. The two distortion sections - one from the EHX Crayon and the other from the EHX Hot Tubes - can be used individually, or together.

  • The Hot Wax is built into an all metal enclosure that measures 4" W x 2" H x 4.5" D. The case is bare metal, with the exception of the graphics on the top.

  • Graphically the pedal is fairly sparse, with a drawing of a green crayon melting on a red-based tube at the center of the Hot Wax logo in the center of the pedal being the main visual attraction.

  • The 1/4" input and output jacks are mounted on the two sides of the pedal. Input impedance is 2.2 M Ohm, while the output impedance is 220 Ohms.


  • The Crayon overdrive section is on the right side of the pedal. This side of the pedal has a green pinstripe outlined in black wrapped around the perimeter, and the two white knobs (with black indicator lines) associated with the Crayon section have similar green and black labels too.

  • The Crayon is a full-range overdrive, and of the two, it tends to have a somewhat warmer sound, with a bit less treble edge. It's still a full-range overdrive, but it seems to have a bit more mids and lows than the Hot Tubes does when both are set identically. This is my first exposure to the Crayon, and I really think it pairs exceptionally well with the Hot Tubes.

  • There are two white knobs that control the Crayon section of the pedal - a Drive knob, and a Volume knob. Drive sets the amount of grit, while the Volume knob sets the output level. Most of my preferred settings were with the Drive set to noon or higher, and the volume set to taste.

  • The Hot Tubes half of the pedal is bordered in a red pinstripe hat's outlined with a black border, and the corresponding white knobs (this time, with red indicator lines) are also labeled in the same red and black motif.

  • The Hot Tubes is one of EHX's older pedal designs, and a pedal I've previously reviewed… it uses a CMOS FET as the heart of its circuit, and it produces overdriven tones that lean towards bright and raspy in character. Like the Crayon, it's a bit different than your typical mid-boosted TS-style overdrive, with a brash and aggressive sonic character.

  • As with the Crayon section, there are two white knobs that are dedicated to the Hot Tubes side of the pedal - Drive and Volume - and they work as you would expect, with the Drive setting the amount of grit the Hot Tubes section generates, and the Volume knob acting as its output control. The Hot Tubes has a bit more treble than the Crayon does, and can generate some nice, rude and raspy sounds on its own, and when driven by the Crayon, it gets massive sounding.
  • The Crayon side drives the Hot Tubes side in the Hot Wax; the volume knob of the Crayon determines how hard you're driving the input of the Hot Tubes, and the Volume knob on the Hot Tubes section sets the overall output level of the Hot Wax.

  • Each of the two overdrives has its own dedicated footswitch. These are located at the bottom of the pedal, with one for each "side" of the pedal. Each switch has a corresponding LED positioned just above the switch to indicate status.  

  • Just as with the somewhat subtle green and red labeling of the Crayon and Hot Tubes sections, the LEDs have the same color coding, with a green LED that lights up when you kick on the Crayon section, and a red LED that illuminates whenever the Hot Tubes half of the pedal is engaged.

  • Directly below the row of four white knobs are another three knobs. These are visually different, so they stand out - they're black with white indicators. These three knobs are active whenever the Hot Wax is active, whether you're using the Crayon, Hot Tubes, or both of them together.

  • Two of the black knobs are Bass and Treble EQ controls. The EQ knobs are flat when set to noon, and can boost or cut, depending on which way you turn them from there.  The EQ is plenty powerful, and allows for a wide range of tonal shadings.

  • The third black knob is a Blend control. This lets you blend in some of your dry, undistorted signal to give the sound more definition and clarity. Turn it down all the way for full dry, and crank it to the max for full distortion. While this is somewhat useful for guitar, it's really helpful when using the Hot Wax as a bass pedal - a job it's very well suited for!

  • The inside of the Hot Wax contains no user-adjustable parts, but here's a "gut shot" to satisfy your curiosity. The Hot Wax uses primarily surface mount construction, which helps to keep the construction costs low, allows for a more complex circuit to fix inside in a smaller enclosure, and helps to keep the quality consistent.


  • Powering the Hot Wax is handled by the included EHX 9V DC adapter. The power input jack is located at the top of the pedal, and uses the industry standard 2.1 mm center-negative plug format. Current draw is 75 mA at 9V DC.


  • The Hot Wax uses buffered bypass switching. I noticed no negative tonal issues associated with it, and in fact, it helped to keep the signal levels nice and robust when using the Hot Wax with several other true bypass pedals connected after it.


  • Unfortunately there's no way to change the order of the two overdrives so that the Hot Tubes could be used to goose the Crayon. The Crayon always runs first, with its output feeding the Hot Tubes.

  • Similarly, there is no way to assign the EQ to any other location in the signal path - it is always post-distortion, and comes after the Hot Tubes.

  • You don't get individual EQ sections for each overdrive - just the master EQ, which influences the tone of both overdrives simultaneously.

  • The Hot Wax does not accept batteries, and can only be powered with an adapter.


Tone savvy guitarists have long known that complex overdrive tones can be generated by "stacking" two dirt boxes and running the output of one into the input of another to generate sounds that neither could make on their own, and that's exactly what the Electro Harmonix Hot Wax is all about. Take two classic EHX overdrives - one of their oldest models, and one of their newest, and put them together, and the combination is even greater than the sum of the parts.

As usual, there's a few things that I would like. It would be great to have a switch that changed the order of the two distortion sections so you could drive the Crayon with the output of the Hot Tubes as an alternative to doing it the other way around, and it would also be nice to have separate EQs for each overdrive, or the ability to put the EQ pre-distortion, but that's really it for my wish list. EHX really did come up with a very cool sounding pedal by combining the Crayon and the Hot Tubes in one housing. The inclusion of the Blend knob opens up a surprising amount of extra tonal textures… bassists will love it, and yes, this is a very bass-friendly pedal (it works great with keyboards too!), so guitarists, keep a tight grip on yours or your band's bassist or keyboardist may decide to borrow it from you on a "long-term" basis. Tell them to keep their hands off and go get their own - I'm betting you'll want to hang on to yours once you give one a try! -HC-

Want to discuss the EHX Hot Wax or have questions or comments about this review? Then head over to this thread in the Effects forum right here on Harmony Central and join the discussion!


Electro Harmonix Hot Wax Dual Overdrive pedal ($148.90 MSRP, $111.70 "street")

Electro Harmonix Hot Wax Dual Overdrive product web page    

You can purchase the EHX Hot Wax from:


Guitar Center    

B&H Photo Video  

Musician's Friend    



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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