Home > Circuits > Guitar Fuzz Amplifier
Modified:20:50, 22 October 2013
CIRCUIT #1 DESCRIPTION

This is a classic design using an inverting amplifier with diodes in the feedback loop. The output is limited to +/- 0.7v causing a clipping effect for any signal greater than that.

A potential divider creates a phantom 0v rail for the non-inverting input to the op-amps. This eliminates the need for a split power supply.

VR1controls the gain of the amplifier which varies from 1 to 100. At minimum gain the signal for the most part remains unaffected. As the gain is increased more of the signal will be clipped but the output should not rise above 1.5v peak to peak. The input should be a standard 500mV. Any more and the clipping will be more severe even at minimum gain.

SW2 switches the unit in and out as required.This can be a foot switch or something similar.


Download circuit simulation (save to file first)


Testing with 1KHz @ 450mV RMS sine wave - viewed on Crocodile Clips


With minimum clippingWith maximum clipping


CIRCUIT #2 DESCRIPTION

This version is intended to run directly from a guitar and then to a power amplifier.The output from the guitar should be feed directly into the input. Use any volume control on the guitar to control input level.

A potential divider creates a phantom 0v rail for the non-inverting input to the op-amps. This eliminates the need for a split power supply. The current consumption is very low, around 3mA so will run from a PP3 battery for some time.

IC1 is an inverting amplifier with a gain of around -100. This will deliver around 500mV from a 5mV signal. VR1controls the gain of the amplifier which varies from 1 to 50. At minimum gain the signal for the most part remains unaffected. As the gain is increased more of the signal will be clipped but the output should not rise above 1.5v peak to peak. The input should be a between 2-5mV. Any more and the clipping will be more severe even at minimum setting.



Download circuit simulation (save to file first)

Written by Phil Townshend 2008
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