Funktronic Envelope Filter


I just finished assembling this nifty little effect pedal. What we have here is what started a rehouse job that kind of mutated into it’s own thing. Years ago, I built a clone of an old MXR Envelope Filter from Tonepad. I’d modded it for bass by adding a “Deep” switch that added a couple of larger capacitors to lower the range of the sweep. Additionally, I’d added a couple of other mods recommended by Mark Hammer on

Of course as with all bass effects, there was a sort of loss attack and low end which made using the filter onstage in a band situation a little uninspiring. I had decided to add a blend feature which would mix a little of my dry signal with the wet signal. Initially, I’d opted for a B.Blender circuit, but there wasn’t a pre-made PCB available. Looking around at some other options out there, I discovered the Paramix on The Paramix is a really cool pedal that would allow me not only to blend my dry signal with any effect in the effect loop, but would allow me to blend two separate effects independently of one another. Realizing that the Paramix was indeed a very powerful tool by itself I decided it would be best for me to make a box that would serve both the Paramix and the EF together.

Realizing that this would be a fairly cumbersome set of circuits, I came to the conclusion that I would need a larger enclosure. I found a really nice sloped steel enclosure over at David make these custom enclosures himself and they come in standard sizes. However, he happened to have had this extra large one laying around and he sold it to me at a very reasonable price. I gave it a little design that was my attempt at paying homage to some of the really cool looking old effects pedals of yesteryear such as units produced by Maestro and Mutron.


The Paramix was a bear of build, mostly due to my ineptitude. Thanks to the guys over at I was able to troubleshoot and get it working. They were a tremendous help. After a really specific round of troubleshooting instructions, I was able to find that one of the pins on the IC socket would not make contact with the circuit board. They advised me to stick a little jumper in there to make the pins make better contact.

In the end, the pedal works and sounds great. I put the two side by side as separate effects, mainly so I could place Envelope Filter anywhere in the effects loop chain. The Paramix does a brilliant job blending the wet and dry signals together and really brings out the low end in my filter. I can pretty much dial in the Isley’s Fight the Power tone instantaneously. Even better, it also unlocks the awesomely funky potential of the otherwise useless reverse sweep mod. Yay!



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