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Electra Complexities

I built the ultra-simple Electra Distortion as my sixth or seventh project after beginning DIY pedal construction, and while the sound was good, it wasn't great. However, the ultra-simple projects have always seemed most endearing to me (such as the Bazz Fuss), and that saved the Electra Distortion from the scrap heap of other good-not-great circuits.

The circuits I build usually fall into two categories: part of the starting lineup or a schematic filed away with notes of how it never made it off the breadboard. The Electra Distortion has been in the lineup since its construction and subsequently gets played with every so often. I believe it was after purchasing an MXR Blue Box that I noticed a strange feature of the Electra Distortion.

The low E string was producing an octave down when single notes were played. Mystified by it, I checked the battery and transistor orientation, but everything was fine. Playing with it some more, I observed that the octave-down was most apparent when keeping my pickup selector switch in the middle position (with both a humbucker and single coil on). When a single pickup was selected, the octave-down was much less noticeable. Since the two pickups are in parallel when both are on, I surmised that the octave-down was related to the source impedance of the guitar. Placing a jfet buffer before the Electra Distortion confirmed this.

I then breadboarded the same circuit, to confirm that this was a characteristic of the circuit and not caused by an error in construction. The breadboarded version produced the same effect. I changed the input capacitor of the breadboard circuit, normally .1uF, to a larger value. The octave-down disappeared. Next, I changed the diode pair. The version I built used a silicon 1N4003 and germanium 1N34A as the clippers. Changing the pair to both silicon or germanium altered the texture and volume of the sound (as usual), but when I used a germanium and silicon in series or an LED, the octave-down effect was lessened.

I recorded two sound clips of the octave-down effect produced by the Electra Distortion, available on the Sounds page. One interesting feature of the octave-down is that it exhibits touch sensitivity. Plucking the string very hard resulted in a very pronounced octave-down, while when playing very lightly, there was virtually no octave-down. As stated above, the effect is heard mostly on the low E string, but can be heard up to the seventh fret of the A string.

Build one for yourself and check out the weird octave-down of the Electra Distortion. A schematic is available on Justin Philpott's page in the schematics section.

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