1969 owners manual for the Les Paul Personal and Les Paul Professional guitars. Both guitars are fitted with "advanced design" low impedance humbucking pickups. "Low impedance pickups offer a new concept in tonal response. The frequency response, tonalities and range of harmonics will exceed that of any electric guitar on the market to date."
Naturally these differed somewhat from the typical Les Paul PAF-style humbuckers, and had quite different controls to match. There was a master volume, master treble and master bass, an eleven position decade switch that "tunes the high frequencies", phase switch (puts neck and bridge pickup out of phase with the other) and tone switch.
The Tone switch is very clever if a little misleadingly named. It doesn't itself alter the tone; rather each position overrides some of the controls - allowing the player to switch between three drastically different control combinations only using one switch.
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