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ZVEX Box of Rock

Updated: Sep 15, 2022

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Zvex Box of Rock
ZVEX Box of Rock Vexter Series


ZVEX is a company that needs no introduction and you’re bound to have heard of their Fuzz Factory, made famous by players such as Matt Bellamy of Muse, who even has the effect installed directly into a number of his guitars.

The Box of Rock is based on a 1966 Marshall JTM45 cranked to breaking point and is designed to deliver all the inherent crunchy chewiness you’d expect from such an amp – it’s like your favourite chocolate bar wrapped in a brushed metal casing. It’s also not a new pedal at all, but that doesn’t mean it’s not worth checking out!

As you’d expect from a company that names the distortion circuit the ‘Distortron Engine’ the appearance is a little quirky – I like to think of that as character though.

This particular pedal was of the Vexter series, which contains all the same parts as the hand painted versions but is screen printed instead. This means the costs can be kept down and so the pedal is a little cheaper – and that’s fine with me! Personally, I really like the printed picture of a Marshall on the front anyway.

There are only four controls and everything is pretty simple with this pedal, unlike many we see nowadays that have 2 or more mini toggle switches for different clipping diodes and loads of dials that can just be confusing. This pedal kind of hold true to the non-master volume amp that is its inspiration: it’s simple and does only one thing, but it does it really well.

Ok, it does 2 things really well as there is also a boost switch, which is a great addition as it’s similar to the Zvex Super Hard On and has huge headroom on tap. This is a really clean sounding unity-to-50-times boost which can be used either in conjunction with the Box of Rock main gain tones or independently to push the front end of your tube amp, or punch through for a solo.


There are only four controls, and they are pretty self-explanatory:

Boost: Increase for more boost.

Volume: Increase for more volume on the Distortron Engine

Tone: Increase for more treble.

Drive: Sets the amount of distortion, or Distortron.

There are two foot switches, one for the boost side and one for the drive side.

On the front of the pedal, you may have noticed the words: ‘Crackle ok’ written next to the Boost and Drive controls. This is just a heads up as when these parameters are adjusted you, will hear a crackle.

This is because the controls also result in a change in the bias and not just because the potentiometers used are cheap and nasty. There is no crackle at all when playing, just when adjusting, so it really shouldn’t be something that will have any negative impact. There are many other pedals that work in a similar way for example, Zvex’s Super Hard On for one, but also lots of fuzzes.

Demo - Check out the video here:


For my demo and review of this pedal I used my Two Rock Studio Pro 35 and a matching 2x12 cabinet, which if you’ve read any of my other reviews, you’ll know is my preferred pedal platform as it has lots of headroom, but responds with great warmth and dynamics.

The guitars used were a Suhr T-Style Andy Wood with Woodshed single coils and a Frank Hartung Embrace with Haussel humbuckers, which is similar to a custom quality Les Paul in feel and tone. These were played through good quality Cleartone cables and recorded with an SM57 at about 2 inches away from the speaker at the cone edge.

The SM57 went straight into an Apollo Twin interface and the signal was recorded using Pro Logic X.

I also used a GigRig modular power setup using an isolator for all pedals to ensure as clean a supply as possible. If you prefer to use a battery, you can as it takes the standard 9v type but most of you will probably take advantage of the standard 9v centre-negative input and use your power supply of choice.

As we’re talking power here, I just thought it also worth mentioning the power draw of the Box of Rock, which is only 3mA. So if you do choose to use a battery, you’ll have hours and hours of playing ahead of you knowing that you have a totally isolated supply.


I started off by increasing the drive control and checking out the crackle. As I said, there is one for sure when making adjustments, but it doesn’t affect playing whatsoever and the pedal was silent all the way up when not moving the dial. It’ll go from a slight crunch to AC/DC levels of gain quite comfortably; a definite rock machine, but not suitable if you want anything with much more drive. But then again, the Marshall JTM45 isn’t often the amp of choice for high gain players anyway.

The tone control has a surprisingly wide sweep and can get both very dark and pretty bright, so there’s no doubt it’ll cover a wide variety of different guitars that are out there.

There is also a lot of volume available even without engaging the boost and the Box of Rock was able to start pushing the tubes in the Two Rock in a very musical way before reaching the top of its output. In fact, this is worth dwelling on a little as it’s actually quite surprising how loud this pedal really is. The manual suggests starting with the volume at around 9 o’clock and adjusting from there, which is much lower than many pedals which will commonly be at unity at more like one o’clock on the dial.

The icing on the cake, though, is the Boost, which elevates this pedal above many of its competitors, which, to be honest, its tone does all by itself anyway. It’s warm; it’s clean; it’s loud and I love the fact that a great quality and very clean boost has been combined in this pedal and that it still has such a small footprint. It measures only 4.7” x 2.38” x 1.82” which is small enough to squeeze on just about any pedal board, and we all like to have just one more drive pedal because you just never know when you might need that extra sound. But even if you don’t really need another drive pedal, this one’s worth having for the boost alone!

The overall tone and feel of the pedal is very pleasing and it really did make the Two Rock feel like a squishy, crunchy, warm JTM45 and inspired me to pull out some old rock and blues licks I haven’t played in some time.

For the demo, I played a simple blues rock rhythm on the Suhr Tele, which maintained great clarity and delivered a wonderful classic rock sound with the Volume just below 12 o’clock, the Tone just above and the Drive bang on. At around one and a half minutes in, you can also hear how nicely the Box of Rock cleans up with picking dynamics as there is a huge difference brought about simply by picking gently. I then played a simple lead line on the same guitar but cranked the Drive to just below max, and while the clarity was still good, the sustain and squish were increased in a very pleasing way.

I then swapped to the Hartung Embrace to hear how the Box of Rock responded to the higher output and more mids inherent in the humbuckers and while I kept the settings the same, I also engaged the boost set to around 1 o’clock. This helped push the Two Rock even harder and resulted in a very useable solo sound: smooth and warm yet with enough treble to really cut through. And, although I keep mentioning it, the feel of this pedal is just great and something that is quite hard to put into words. There’s a compression especially at higher drive settings when you dig in that feels very amp-like and yet the Box responds very well to dynamics too and picking lightly or rolling back on the volume control is very rewarding.


I had a blast playing with this pedal and wish I’d discovered it sooner. If you are after a sound reminiscent of 70s rock or want the Marshall-like warmth and breakup for your blues rig, this pedal really does need to be auditioned; and the fact there is such a warm, clean boost function on top may well just clinch the deal.

The pedal also really rewards dynamic play, so try setting the gain as high as you’d be likely to use it and use the guitar volume to get your cleaner sounds.

A great pedal by Zvex and at around £200 for the Vexter version, you can pick one up used at closer to £120 quite easily.

Definitely worth a play.

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