The Rangemaster is a vintage guitar treble booster that gained popularity for its influence on the tone of electric guitars. Here's a brief history of the Rangemaster:

Creation (1965): The Rangemaster was created in 1965 by Dallas Arbiter, a British electronics company. It was designed by Ivor Arbiter, the founder of Dallas Arbiter, and Barry Pyatt. The primary purpose of the Rangemaster was to boost the treble frequencies of a guitar signal.

Treble Boosting Concept: The Rangemaster was not a distortion pedal but rather a treble booster. Its main function was to emphasize the high frequencies of a guitar's signal, giving the instrument a brighter and more cutting sound. This was particularly useful for players looking to stand out in a mix or achieve a more pronounced lead tone.

Use by Eric Clapton: The Rangemaster gained notable recognition when Eric Clapton used it with John Mayall and the Bluesbreakers.