Wonderful Audio Apex Distortion

The Wonderful Audio Apex is a distortion pedal that started as a RAT-based circuit and ended up becoming its own (still vaguely ratty) thing.

The original idea was to experiment with the vintage RAT’s LM308 chip. A JFET front-end gain stage was then added to recreate the effect you get when you boost the signal you feed to the RAT, which triggered a reworking of the voicing of the LM308’s gain stage’s voicing aimed at a crisper high-end and flexibility at any gain range.

The clipping section was designed to get a blend of smoothness and crunch, while the tone stage was left the hell alone, replicating the RAT’s low pass filter. At the end of it all there’s a JFET buffer which also adds some color as it saturates.

You can hear the results in the video below, we added it to our article about the best RAT pedals, clones, and variants.

Wonderful Audio Apex Distortion, Builder’s Notes

Apex Distortion is a versatile distortion pedal which was originally inspired by a particular LM308 rodent pedal. The goal was to create something new, while still paying homage to the original. This is not a clone. It is a reimagination of a classic. Top of the food chain. The Apex predator.


A while back I saw a set YouTube videos from the incredible Demos in the Dark. The series was called “Rat Week” and each day he showcased a rodent based pedal and compared it to an original. But the key here was that not only must the pedal be based on said circuit, it also needed to contain the fabled LM308 operational amplifier. Now, I’m not saying that the LM308 chip is any better or worse than any other chip, I’m just saying it’s a cool chip and I wanted to use it. I decided to challenge myself to design a pedal around that chip with a circuit inspired by the said rodent pedal. So… I found some LM308s and got to designing. The pedal went through many revisions, in fact I had a version that I almost released. I really liked it, but I felt after playing it at band practice a few times, I thought I could do more… it needed more toanz for my snobby ears. I wanted to improve some aspects of the original by increasing its versatility, improve the gain range, smooth and thicken the tone, while still maintaining some bite.

Circuit Breakdown

First things first, I love boosting the RAT with another drive, bit so I added a JFET front end gain stage. JFETs are great because they react extremely well to the dynamics of your playing… dare I say it?… are very amp-like in their character. Next is the LM308 primary gain stage. I completely changed it’s voicing. I wanted a nice low punch with crisp highs and it had to preform well in both low gain and high gain situations. Next is the clipping section. I wanted to a blend of smoothness and crunch so I combined a mixture of diodes and an LED. Up next, the tone stage, which similar to the RAT, functions as a classic low pass filter however it is reversed so to the left is darker, right is brighter. Finally in true classic form a JFET buffer which also adds some color as it saturates.