Not your dad’s diode-clipping distortion.
The WaveFunction is a diode-clipping distortion with a difference.
Clipping diodes are the secret sauce in countless overdrive circuits. When a diode pair is configured in inverse polarity, it literally clips off part of each audio wave, spawning distortion. Clipping diodes appeared in such 1960s transistor fuzzes as the Jordan Bosstone. After IC-based distortions arose in the ’70s, they assumed an even more prominent role.
Sometimes they were downstream from the op amp (as in the Pro Co RAT) and sometimes inserted into the op amp’s feedback path (as in the Ibanez Tube Screamer). And they—not tubes alone—generate much of the crunch on a Marshall JCM800.
Different diode types yield different tones, and diode choice is one of the main points of distinction between today’s countless Tube Screamer spinoffs. Germanium diodes sound relatively smooth and soft. Silicon diodes have a rougher, tougher edge. LEDs even more so. Some clever builders incorporate switchable diode combinations, expanding an overdrive pedal’s tonal range.
The WaveFunction Overdrive, from Canada’s Nanolog Audio, is one such device, but with a high-tech twist. While two of its four settings provide conventional germanium and silicon diode clipping, the other two employ a newer form of diode: a “molecular junction,” or as Nanolog Audio dubs it, a “nano molecular sandwich.”
Hold the Mayo
I won’t even pretend to understand how this “sandwich” works, though Nanolog’s Adam J. Bergren has published a scientific paper on the subject. It sure looks different, though! In addition to conventional germanium and silicon diode pairs (1N34As and 1N4148s, respectively), the circuit board includes a small plastic frame. Inside of it is a tiny wafer that looks a bit like a phone’s SIM card. This is home to the molecular junction diodes.
The two “sandwich” settings are impressive. Hear for yourself: My audio clip begins with a guitar phrase repeated through the four diode settings. As expected, the germanium setting is relatively rounded and warm. The silicon diodes are slightly louder and have stronger note attack. The “N1” setting (the first sandwich) is similar to silicon, but a touch fatter. “N2” is the hottest and most aggressive of all. This is something new under the stompbox sun. (FYI, everything’s recorded through a clean combo amp to keep the focus on the pedal’s innate character. Everything gets gnarlier through a hot amp.)
A Familiar Feel
Gee-whiz technology aside, The WaveFunction sounds and behaves much like a conventional IC-based overdrive. The chip is an LM1458 dual op amp. The diodes are downstream, Screamer-style. Judging by ear alone, few players would suspect anything stranger than a well-chosen diode pair. But they’d probably appreciate the two extra-punchy settings, which, despite their aggression, are uncommonly friendly to chords and dissonant intervals.
WaveFunction includes the expected gain and volume controls. More unusual are the dual passive tone controls—to my ear, a huge improvement on a Screamer-style low-pass filter. Low frequencies disproportionately drive amps and distortion pedals. That means the bass-cut control is both a tone control and a gain control. With big bass cuts, tones get brighter and cleaner. Between the double-headed tone stack and the four diode sets, there’s lots of tonal range here.
The WaveFunction lives in a conventional BB-sized enclosure. It has classy metal knobs and board-mounted plastic jacks. The pot shafts are also plastic. A quartet of LEDs indicate the current diode setting. Despite the high-tech diodes, this is a traditional through-hole build, not surface-mount. The pedal runs on standard 9V power and has no battery compartment.
Nanolog’s WaveFunction Overdrive is both familiar and fresh. In many respects it’s a conventional IC-based overdrive. But its modernistic diodes generate fat, aggressive clipping. Meanwhile, the added bass-cut pot yields colors you won’t get from a Screamer-style tone control. This is a good-sounding overdrive in its own right—and perhaps a foretaste of cool things to come.