Epoch Bias Out Now!

MXR Distortion +

Welcome back, cabineteers! Have you ever thought about the origin of effects names? I definitely have. As long as I’ve been contemplating things like what the word “jazz” actually means and other such things, I also wonder how folks listened to the FZ-1 or the broken console through which Marty Robbins and his band recorded “Don’t Worry” and thought, “hmm, fuzz is definitely the word for this sound.”

Of course, malfunctioning equipment is the greatest invention for electric guitar. Just like the aforementioned bogus console tube, or the Kinks slicing their amps’ speakers to produce more ragged tones, the concept of distortion in general arose from something once seen as an unwanted byproduct of amplification. 

Low-watt tube amps, as we know, can “break up” when the volume is turned up. This wasn’t always ideal, especially as the audiences for electric guitar music became larger and the stage size outpaced the size of amps in general. You want to get loud? It’s going to distort. You want it to stay clean? Buy a bigger amp. Distortion was persona non grata in those days, and amp manuals distinctly warned players not to turn up too loud, lest your guitar sound broken, or just downright unpleasant. 

Over time though, this became a desirable trait, and there is perhaps no bigger piece of evidence than effects produced specifically to distort a signal and then feed that distortion through a loud clean amp. What a difference a few years makes to completely flip the very function of gear 180 degrees. This pedal is the MXR Distortion+. 

Many fuzz pedals danced around the idea that a signal should be distorted when it hits an amp, but not like a pedal like the D+ that put this sound in amp terms. While fuzz units provided a tone that was quite literally modeled after electrically malfunctioning equipment, the D+ made your amp sound like a naturally distorting amp, more or less. Did it sound like “your amp”? Not exactly. But it did sound like “an” amp, that’s for certain. 

Now that we live in an era where overdrive pedals have 12 knobs, the idea that someone can skirt by without so much as a tone knob is rather droll. But when you’re first at bat, you can either hit or strike out, and MXR hit. Much like the company’s other products, the simplicity and actual tones were a revelation in the mid ‘70s. Manufacturers both domestic and foreign descended on MXR’s designs and used them as a foundation to launch their own lines. Ross Electronics of Chanute, Kansas was one such company, as was Japan’s Coron among many—almost innumerable—others. But it was MXR that coined the term “distortion pedal” and made monstrous cranked amp tones accessible to apartment dwellers and beginners. 

By today’s standards (and even compared to the other pedals in MXR’s 1970s catalog) the parts count and overall topology is rather demure. Popping the lid of the D+ reveals a sparsely populated board with just a handful of components, including three simple semiconductors. By contrast, the Blue Box or Phase 100 were lousy with parts, filling their boards to the brim. 

The distortion engine of the D+ is a simple op-amp with a large 1M pot setting the voltage gain. At minimum, the Distortion knob delivers just 3.5dB of gain, but at maximum there’s 46.5dB of gain, a full 11.5dB more than the next benchmark in purposeful distortion, the Boss DS-1. Yes, that is loud. But right before reaching the output jack, the signal is clipped by a pair of anti-parallel germanium diodes that clip the waveform heavily, leading to distortion. If you were to take a pair of wire cutters and remove these diodes from the D+ board, you would dramatically increase the volume at the expense of saturation. 

This acts sort of like an amp, in a roundabout way. The forward voltage of the diodes ensures that the signal is clipped once it passes a certain threshold. And until the player crosses that threshold, the diodes won’t turn on and the signal remains unaltered by them. Turning the distortion control up amplifies the signal to intentionally clip and compress, which sounds an awful lot like tube amp distortion if you squint your proverbial eyes. 

Despite its no-frills facade, the D+ is quite an important piece of gear history and has served as a crude blueprint for what distortion effects would become in the future. I love it and if you haven’t played one, you’re cheating yourself.