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ZVex Vextron Series Mastotron Fuzz Guitar Effects Pedal  

Product #620301

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Item Note:

This product has been discontinued but may be available as a Open Box item.

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Get blistering hot fuzz with this raging pedal.

The ZVex Mastotron Effects Pedal, another in the Vextron series, is a heavy silicon-based fuzz pedal with a lot of controls-volume, tone, pulse width, fuzz, and relax/push. The relax/push controls the input impedance to the pedal. The guitar effects pedal knobs let you adjust for quieter pickups, or softer guitars, and turn it towards the relax setting as you put in active pickups, and turn it all the way to the relax setting for special effects and for line-level signals if you are re-amping a bass off a recorded track. The Mastotron's fuzz control is a wide control over the fuzz depth. Pulse width control goes from a narrow pulse all the way to a nearly square wave pulse. The tone control shaves off the high end. A sub switch lets you set how many subs you have with a "2-1-3" arrangement while the dedicated volume knob controls how loud the guitar pedal gets.

Plug your guitar (or any effect's output) into the input jack. Plug the output into an amp or other effect's input. Set the amp for a warm clean tone on bypass. Turn on the pedal and rock out. Using a guitar or bass, turn the Relax/Push knob down a bit if you need to until the fuzz sounds immediate and tight. Turn the Vextron Mastotron's fuzz control until you're happy, and set the PW to square (counter-clockwise). Adjust the tone for the treble amount you want, and use the sub switch on 3 for full heavy subs for bass or 2 if the subs are overloading your amp.

Set your amp on your favorite clean tone for the most blistering results, while a distorted sound can be very cool as well. Play it into your favorite distortion pedals or direct into the amp for different textures. Try putting weird effects into the ZVex Mastotron pedal and adjust the Relax/Push knob for best interfacing.

If the performance of your fuzz pedal seems diminished or the LED becomes very dim, it's time to change your battery. Remove the four screws on the bottom of the effect pedal and carefully remove and replace the old battery, putting it back exactly in the center of the pedal on edge so that it is gripped tightly by the lid when it is screwed back in place.


  • Relax/Push knob
  • Fuzz knob
  • Pulse width control
  • Tone control
  • Output volume control
  • Subs switch: "2-1-3" Lets you set how much sub content is in your fuzz. It's pretty dramatic”3 is huge, 2 is medium, and 1 is absolutely none left.

Plug it in and get your fuzz on. Order now.


Vextron Series Mastotron Fuzz Guitar Effects Pedal Specifications:

  • Uses one 9V battery (preferably alkaline, but the unit is shipped with a carbon-zinc battery.)
  • A DC power jack (standard Boss configuration with center negative) is provided on the side of the pedal.
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by PowerReviews
ZVexVextron Series Mastotron Fuzz Guitar Effects Pedal

(based on 2 reviews)

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Reviewed by 2 customers

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Sweet Fuzz


from Mohave Valley, AZ

Comments about ZVex Vextron Series Mastotron Fuzz Guitar Effects Pedal:

This pedal is very dynamic and versatile. I have found so many tones inside it. The controls are very interactive so small movements can change the sound a lot but that is the key to maing this pedal so useful. The subs switch is great and can go from thin and fizzy to thunderous. The relax push knob is also a great feature and I wish that it came on more fuzzes.


The last Fuzz I'll ever need


from Undisclosed

Comments about ZVex Vextron Series Mastotron Fuzz Guitar Effects Pedal:

I have been extremely happy with my Mastotron Fuzz since i got it. This pedal lives up to the hype that surrounds Zvex. I have many fuzz pedals including an old Big Muff, Maestro FZ1B, Boss FZ-5 etc. and the Zvex does all my favorite tones. The relax control allows me to tweak it for all my guitars from the weakest pickups to bass and even works great for synths. I like the switchable low frequency response as it makes it work great with my old Ampeg Gemini II which needs a little less bass. With the full bass response it makes my Electar 10, Fender Pro Jr and Vibro champs have a great corpulent tone. As a long time electronic tech and designer I am impressed by the useful range of all the controls. The PW control does a great job of delivering a wide range of fuzz characters going from a smooth 60's sound to a fizzy but useful edgy tone. I like it so much I hate to switch off. Worth every penny!!

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