Moreland Magnetics 202a Harmonic Percolator

Ah, the Harmonic Percolator. A mystery wrapped in a riddle wrapped in…well, distortion and fuzz and octave-bending and lots of other stuff. It’s always impressed me how two knobs are capable of doing so much, and I’m excited to have another example for you all today. The 202a Harmonic Percolator from our new friends at Moreland Magnetics features that same two-knob design, but integrates countless hours of testing and some vintage components, as well as a hidden feature under the hood. Time to get down n’ dirty, kiddos – let’s see what this beige beauty is capable of, shall we?

The 202a is Moreland Magnetics’ take on the inimitable Interfax Harmonic Percolator, an unruly tone machine renowned for its suppression of odd-order harmonics, slight octaving effects, and chewy, gnarled distortion sounds. There are about as many variations on this circuit as there are people willing to build them, and this is just their particular take. The crucial components here are the vintage Si & Ge transistors, and a pair of these *specific* and hard-to-find germanium diodes. Each set of NOS components is measured for gain and then audited by ear to make sure they do The Thing.

Each of these machines have the potential to interact drastically differently with guitar, pickup selection, pedal stack, and amp. At once you’ll notice a fierce, unforgiving upper midrange bite, with a lower octave undertone supporting your notes as you move up the fretboard, almost like an Octavia tone but inverted. Dialing back the knobs transitions unruly, mangled chaos into a surprisingly usable overdrive tone. Many tend to like this in front of a slightly overdriven amp, or stacked in front of another gain pedal as a tone shaper. Use it like a Fuzz Face and roll your guitar’s volume back for slinky, jangly overdrive with the roar a mere touch away.

There’s even an internal trimpot that lets you adjust a variable resistor that will change the frequencies where the octave thing happens. The stock setting is fantastic, but further sonic exploration is available, should you be so inclined. This wasn’t my first foray into the world of the Harmonic Percolator, and I don’t think there’s one I’ve played that I haven’t thoroughly enjoyed – that streak 100% continues with the 202a. Be sure hit up the Moreland Magnetics website for ordering and more info, right after you check out our demo video (and sunbscribe!) over on our YouTube channel – cheers!!