3 Leaf Audio Chromatron Review

If you’re a pedal junkie like myself, you are likely familiar with Seattle-based 3 Leaf Audio. 

I remember when their ‘Groove Regulator’ envelope filter first hit the scene, making waves with how powerful, versatile and straight up funky it was. At the time, there wasn’t much in that smallish form factor that offered that much control over the envelope filter behavior. Naturally, the Groove Regulator was a hit, as were (and are) many of 3 Leaf’s iconic pedal designs.   

Following the success of the Groove Regulator and incorporating important feedback from players, 3 Leaf launched the Wonderlove envelope filter, which many still consider the high-water mark for envelope pedals.  The Wonderlove tied in some improvements to the Groove Regulator, with a few notable additions that made it even cooler and more usable for bassists.  

Now, on the heels of the highly successful Wonderlove, comes the Chromatron.

As 3 Leaf says,“the Chromatron is the result of 10 years of tweaking, refining and reimagining the state variable filter circuit.”  

At its core, the Chromatron is an optically controlled analog filter.  Its dual footswitches allow users to toggle the effect on/off and also to switch between “envelope filter” mode and “expression pedal” mode for manual control of the filter, with an external expression pedal, giving it a “wah pedal” type of control. All of the controls are well thought out and give the user a huge degree of control over the filter parameters. 

Housed in an undeniably boss looking brushed metal casing, the build quality and feel of the pedal couldn’t really be of any higher quality.  

It is exceptionally robust and well designed.  The knob feel is smooth with nice resistance, making accidental knob bumps a non-issue.  I loved the Spartan look and feel of the Chromatron, and the row of top mounted jacks are always nice to see when pedalboard real estate is at a premium.

There are a number of great things about the Chromatron, but I’ll stick with what I consider the coolest and most unique.  

The Chromatron’s FX loop (much like the Wonderlove) allows you to run pedals in its loop, sonically placing those effects before the envelope filter, but using the clean input signal so that the triggering of the filter can remain at a consistent level.  Did I lose you? Imagine you want to run a chain of octave > fuzz > envelope filter, but you also want to be able to run just your envelope filter with your bass.  If you set the “response” knob (the input level/filter sensitivity control that sets the trigger point of the envelope filter) so that it is optimal for your clean bass, but then you kick on the fuzz or octave, and the signal often gets hotter, you lose that perfect balance of filter responsiveness that you just dialed in. With the Chromatron’s FX loop, the filter “sees” your clean bass signal in terms of how the filter is triggered, but the signal path remains octave > fuzz > envelope, as desired. (Side note: for maximum fun, the FX return can also be employed to use any additional sound source in order to trigger its filter.  (Try it with a kick drum mic, trust me.)

It is these types of smart innovations like this that make the 3 Leaf stand out, as they are clearly designed by someone with working knowledge of what players need and want. 

One of the Chromatron’s allures is that it is complex but immediately intuitive.   

I was able to hone in on my preferred envelope sounds pretty quickly, and it delivered some supremely musical classic tones.  I loved how easy it was to tweak the parameters and get it just right for pretty much whatever I was going for. 

I have to admit; envelope filters have come a long way since I first became infatuated with them. My journey started with the good ole green 2-knob DOD FX25, and then the Electro Harmonix Q-tron, in all its big and clunky glory.  Then I moved on to a dozen or so more, each one cool, but missing some kind of necessary practical requirement or limitations in its sound. The Chromatron packs so much control and versatility into a compact user-friendly package, with style and grace.   

If you’re looking for the funkiest of the funk, the Chromatron should definitely be on your list.     

The Chromatron sells direct from 3leafaudio.com for $349.