Weak 9 Volt Batteries: Secret to a Great Fuzz Pedal Tone?

Even though batteries for wireless units and guitar tuners should always put-out full 9-volts when tested on a voltmeter, can weak 9-volt batteries in your Fuzz or distortion stompbox give you great tone?

By: Ringo Bones 

I might be the last person to know about this electric guitar “tone tweaking” trick during my amateur metal band days back in the late 1980s, but it has been empirically proven by guitar gods and guitar techs since the days of Woodstock that a weak 9-volt battery that only puts out between 5.5 to 7.5 volts when connected to a voltmeter can actually result in a pleasing tone when used to power your Fuzz or other distortion type stompbox effect pedal. Famed guitar legend Duane Allman reportedly preferred weak batteries in his Dallas Arbiter Fuzz Face, though any voltage reading lower than 5.5-volts – and depending whether your distortion pedal is IC op-amp or germanium transistor based – it could be the difference between “death metal tones” to a dead as a doornail silent stompbox. But why do weak 9-volt or PP-3 batteries produce a pleasing tone when used to power your Fuzz Face / distortion type stompbox effects pedals?  

The “subjectively pleasing tone” one gets when using weak 9-volt PP-3 batteries on their distortion pedals is probably a holdover from the days before the invention of more efficient solid-state silicon rectifiers. Where electric guitar tube amplifiers still use vacuum tube power supply rectifier and / or selenium rectifier based power supplies when a hard-struck power chord usually causes power supply voltage sag and the accompanying warm fuzzy distortion tone – and unlike your typical hi-fi vacuum tube amplifier, this “fuzz tone” is usually in the 200 to 300 percent total harmonic distortion range. Though there are some electric guitar vacuum tube amplifiers like use both vacuum tube and solid-state rectifiers – Mesa Boogie for example – for reasons of tone. This makes the GZ34 vacuum tube rectifiers, especially the NOS Mullard types, are now highly sought after by vintage guitar amp enthusiasts. If only Mullard made reliable versions of those pesky selenium rectifiers used in the Fisher 500 C Receiver.