Power valves can be overdriven in the same way that pre-amplifier valves can, but because these valves are designed to output more power, the distortion and character they add to the guitar’s tone is unique.

Because driving the power valves this hard also means maximum volume, many solutions have emerged that in some way divert some of this power valve output from the speakers, allow the player to generate power valve distortion without excessive volume. These include built-in or separate power attenuators and power-supply-based power attenuation. Lower-power valve amps (such as a quarter-watt or less), speaker isolation boxes, and low-efficiency guitar speakers are also used to tame the volume.

Although traditional amplifiers were complete circuits including both preamp and power amp, power-valve distortion can also be produced in a dedicated rackmount valve power amp. A modular rackmount setup often involves a rackmount preamp, a rackmount valve power amp, and a rackmount dummy load to attenuate the output to desired volume levels. Some effects pedals internally produce power-valve distortion, including an optional dummy load for use as a power-valve distortion pedal. Such effects units can use a preamp valve such as the 12AX7 in a power-valve circuit configuration (as in the Stephenson’s Stage Hog), or use a conventional power valve, such as the EL84 (as in the H&K Crunch Master compact tabletop unit). However, because these are usually placed before the pre-amplifier in the signal chain, they contribute to the overall tone in a different way.

A Direct Inject signal can capture the power-tube distortion sound without the direct coloration of a guitar speaker and microphone. This DI signal can be blended with a miked guitar speaker, with the DI providing a more present, immediate, bright sound, and the miked guitar speaker providing a colored, remote, darker sound. The DI signal can be obtained from a DI jack on the guitar amp, or from the Line Out jack of a power attenuator.