Volume Pedal Modification with Redeemer Circuit Buffer

By Guitar Kit Builder
Feb 17, 2011
in Guitar Kit Builder - Pedals & Effects

If you use a volume pedal and find that it effects the tone of your guitar, this modification may be just what you need. It uses a handy module made by the folks at Creation Audio Labs. This module, named the "Redeemer Circuit" is a buffer amplifier circuit that eliminates tone loss caused by the interaction of instrument electronics and the loading effect of the cable, effects units and amplifier. If you're not familiar with the term, a "buffer amplifier" is an amplifier made to transform the impedance from input to output while not otherwise shaping or amplifying the signal. In other words, it isolates or buffers the input from the output. In the case of the Redeemer Circuit we have a voltage buffer with a very high impedance input and a low impedance output. This means that whatever loading we place on the output will not sap the tone of the guitar. By insulating the instrument from the rest of the signal chain we obtain the following benefits:

Greater Note Clarity - Individual notes within chords are heard with greater detail. Higher frequency signals such as harmonics are especially clearer as they tend to be the most affected by circuit loading.
Improved Transient Attack - the instrument sound becomes more responsive to the player's picking velocity and strength.
Greater Linearity and Transparency - The timbre of the instrument stays consistent, especially when “rolling back” the volume controls. This reduces any loss of high frequencies when you turn down your instruments volume.
Feed Directly Into Mixer Line Input - Because the output impedance is less than 300 ohms, the circuit can easily drive the line input of a mixer. This results in a clear, full range of tone that sounds better than using a direct box for live or recording applications.

Here are Creation Audio Lab's specifications for the Redeemer Circuit: Flat frequency response: 10 Hz - 50 kHz! Noise floor: -125 dB! Distortion: 0.0005% Input Impedance: > 2M ohms Output Impedance: < 300 ohms Current Draw: < 2.5mA Power: operates from 9v to 18v Phase response: between +/- 0.1 degree from 20 Hz to 20 kHz Dimensions: 0.4" x 0.8" x 1" (metric = 1.0 cm x 2.0 cm x 2.5 cm) and a 9 volt battery Take a look at this video to hear an A/B comparison of the Redeemer Circuit in use:

While the most common application of the Redeemer Circuit is to install it inside a guitar, the following video illustrates an application where it is placed inside a volume pedal, so that one circuit can be used by any instrument.

At the time of writing the Redeemer Circuit was available from Creation Audio Labs and other sources for $49.