The Fractal Overdrive is a clone of the Pearl OD-05 Overdrive, a strangely obscure effect from the early 80’s when Pearl (yes, the drum company) briefly dipped into the effects pedal business. The result was a line of very well-engineered pedals that unfortunately never got the attention they deserved.
The interesting thing is, even almost 40 years later this pedal still is relatively unknown. There are no commercial clones of this pedal and it’s relatively unexplored in the DIY scene (with the exception of BYOC’s Parametric Overdrive project). But those who have played through one universally praise it for its tonal flexibility.
The OD-05 has a standard feedback-diode clipping stage like a Tube Screamer, but the magic is what comes in front of it: a parametric equalizer that allows either a cut or boost of up to 15dB in a range from 100 Hz to 4 KHz. With this flexible preclipping EQ, you can get some incredible sounds out of it. You can crank the mids for a cocked-wah sound, or tune the circuit to enhance the resonant peak of your specific guitar and amp. You can even get a scooped-mids sound if that’s what you’re shooting for, something that’s pretty rare in an overdrive.
The circuit has a lot of familiar things in common with others you’ve seen, but in this implementation they don’t always behave how you expect. This is not quite a Tube Screamer where you can tweak just about any part and get something good out of it! The original designers balanced the stock circuit very well, but if you’re modifying it, you may find that if you change one thing on one end you may need to change something clear over on the other end to make the first thing sound good.