Review: Henretta Engineering's Tiny Green Zapper Auto Filter Pedal

We’re guitar players, and we love pedals! If our boards, band members and bank accounts would allow it, we’d have tons of them.

Then, all of a sudden, we run out of room on our pedalboard, and it turns into a game show like Survivor or American Idol. Who’s getting the boot? Who will make it back for next week’s show? Will I get to meet Randy Jackson?

Henretta Engineering has released a line of handmade pedals that won’t break the bank or hog up unnecessary real estate.

Of the seven pedals in the series, I checked out the Green Zapper Auto Filter, which, like its kin, sizes up at 2 inches by 2 inches. That’s right, smaller than a Post-It note and even smaller than the Twinkie in the photo at left.

There are no knobs (more on that in a second) and no battery compartment. Now you’re asking, "If there are no knobs, how do you dial in that magical tone?" There are two very tiny knobs or internal trimmers inside the pedal that can be adjusted when you remove the four backplate screws. The two knobs are Sensitivity and Range.

When I got the pedal, the trimmers were set for a single-coil guitar. If you want to use it with humbuckers or a bass, you’re going to have to dial back the sensitivity. You’ll see in my pictures that the trimmers are very small, so adjusting a little bit goes a long way.

It took some getting used to, but I was able to find the sweet spot where dynamics were king. If I played softly the pedal was smooth and musical, the harder I played the fizzier and nastier it got.

The Green Zapper is powered by your standard 9-volt (10mA) barrel negative tip plug. Both the power plug and input/output jacks are side mounted. The switch is true bypass and there’s a bright green LED light to indicate when the pedal is on.

For more advanced pedal fans; you can experiment by replacing TL082 dual op amp. Feel free to contact the manufacturer if you aren’t sure what will or will not work.

For my sound clip (below), I plugged a Strat and a P-bass straight into the pedal and then into a DI. The Green Zapper works great with overdrives in front or behind it, but hey, my clip is to show off the auto filter.

No need for an auto filter, but dig the small footprint? Henretta Engineering also makes boosts, octave, tremolo, fuzz and compressor pedals.

Price: $125

You can't believe everything you read on the Internet, but Billy Voight is a gear reviewer, bassist and guitarist from Pennsylvania. He has Hartke bass amps and Walden acoustic guitars to thank for supplying some of the finest gear on his musical journey. Need Billy's help in creating noise for your next project? Drop him a line at

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