Guitar Distortion Matrix
Here’s a circuit that provides a variety of distortion sounds for the electric guitar. The passive diode matrix should be driven by an active device, such as a volume-boosting stomp-box or guitar preamp, while the output can go to any kind of guitar-amp or other such active device. The design is based on the distortion circuit in a project called the “Mod Box” that appeared in Electronics Now magazine in 1997 (May issue, p. 45). And while the article is old, the circuit I designed based on it remains perfectly valid.
The preferred sounds, emphasizing even-order harmonics, with either the Fuzz, Buzz, or Overdrive settings is to activate only one diode oriented in a given direction but two in the other direction. It does not matter which directions are chosen for the combination as long as there’s an imbalance. Of course, any setting provides distortion. The germanium diodes, in the Fuzz setting, are said to give the most pleasing distortion, similar to that of a vacuum-tube clipping, while the silicone diodes give a harder sound, with the LEDs the brightest.
Because of significant loss of input signal level to achieve the distortion effect, some kind of active device, such as a stomp-box with extra gain, is needed on the input. Or, to turn this into an active project, battery-powered solutions are shown below. Use the preamp to drive the matrix and put the buffer between the matrix output and the input of an amplifier or other active device. And I recommend keeping the input/output jacks as shown, to allow for the greatest versatility, even if everything is put in one enclosure. For the +9V DC supply, connect the negative end of a transistor battery to ground so the positive end is the supply. And one battery will serve both circuits.
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Here’s a circuit that provides a variety of distortion sounds for the electric guitar. The passive diode matrix should be driven by an active device, such as a volume-boosting stomp-box or guitar preamp, while the output can go to any kind of guitar-amp or other such active device. The design is based on the distortion circuit in a project called the “Mod Box” that appeared in Electronics Now magazine in 1997 (May issue, p. 45). And while the article is old, the circuit I designed based on it remains perfectly valid.
The preferred sounds, emphasizing even-order harmonics, with either the Fuzz, Buzz, or Overdrive settings is to activate only one diode oriented in a given direction but two in the other direction. It does not matter which directions are chosen for the combination as long as there’s an imbalance. Of course, any setting provides distortion. The germanium diodes, in the Fuzz setting, are said to give the most pleasing distortion, similar to that of a vacuum-tube clipping, while the silicone diodes give a harder sound, with the LEDs the brightest.
Because of significant loss of input signal level to achieve the distortion effect, some kind of active device, such as a stomp-box with extra gain, is needed on the input. Or, to turn this into an active project, battery-powered solutions are shown below. Use the preamp to drive the matrix and put the buffer between the matrix output and the input of an amplifier or other active device. And I recommend keeping the input/output jacks as shown, to allow for the greatest versatility, even if everything is put in one enclosure. For the +9V DC supply, connect the negative end of a transistor battery to ground so the positive end is the supply. And one battery will serve both circuits.
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