Saturday, January 2, 2021



I am always on the lookout for new and different effect pedals to expand my sonic landscape. The EHX Mainframe distortion pedal looked like a likely candidate so I ordered one up.

The pedal comes with an EHX 9-volt DC power supply capable of delivering 200ma. The Mainframe has a standard external DC power inlet jack which is wired to the industry standard of inner-minus, outer-plus. The beefy external power supply was my first indicator this pedal might be power hungry.  For all of my testing I used the EHX power supply which is a traditional linear type with a heavy iron transformer inside.


The pedal has the traditional input on the right and output on the left. An external expression control input is also present on the right side of the enclosure. 

On top of the panel the knobs are grouped closely together but I found them easy to work with. The pots all are mounted firmly and everything feels high quality. The enclosure itself is cast aluminum with a nice matte gray finish highlighted with bright green branding.

The test guitar was my Gibson SG which is outfitted with Seymour Duncan Pearly-Gates humbucking pickups. I connected the SG into the Mainframe and went into the front input on a Marshall Origin 20-watt combo, the amp was set for a big clean sound.

Controls on the Mainframe allow you to reduce the digital “bit depth“ or reduce the “sample rate" or both, completely variable. These are the principle distortion producers in this pedal, the rest of the controls are for blending, tone and level control.


I found the distortion produced by this pedal to be very irritating, the word "gnarly" describes it well, it's rough and very nasty sounding. Unlike overdrives or pedals that rely on overloading something to make a distorted tone this pedal does it entirely in the digital domain. With the controls set to minimum the pedal passes your guitar virtually unmodified. Grab the Bit Depth and Sample Rate knobs and you’ll learn why they call this pedal “bit crusher”. Turning bit depth and sample rate knobs clockwise rewards you with truly odd distortion effects.

This is not a “pretty” sounding pedal. It does not fit with the style of music I write, the harmonics are not beautiful. Overall the bit and sample reduced effects might work in some form of heavy metal but that is not my domain.

The Filter controls on the Mainframe really help make the output sound a lot more friendly. With some filter control adjustments I could make the bit crushed sound useable as an effect but not really musical. Someone who is into heavy pulsing metal distortion might really like this pedal. It lets you turn on and off chordal sound in unique and dynamic ways.

Running the Mainframe through an echo, slathering it with lots of reverb and/or forcing it through a heavy flanger made some fun odd effect sounds but nothing I really see myself needing in my musical compositions. 

With a street price of $179 this EHX pedal is not what I’d call cheap. Fortunately my supplier lets me return gadgets that don’t work for me. This one was a return for me but for the sonic adventurer who craves intense brash sounds I’d recommend checking out the EHX Mainframe bit crusher.


I purchased this pedal. There are no affiliate links or cross marketing. H.o.T. is a labor of love. Thanks for reading. 

Good music to you!

This article is copyright January 2021 by Mark King. It is not ok to copy or quote without written permission.