The Boss TW-1 Touch Wah was an auto wah/filter that prepared guitarists for the funky 80's. It produced a thick, throaty wah tone and was the first compact filter effect released by Boss. The TW-1 automatically applies a "wah-wah" effect to your signal by detecting the players dynamics, with more pronounced playing leading to a more intense effect.
The TW-1 has 2 knobs and a toggle switch and is one of only 2 pedals (along with the CS-1) to feature this design. The Sens (short for Sensitivity) knob is used to control how sensitive the effect is to your playing dynamics and the Peak knob controls the tone of the filter. The Drive toggle switches between a Down and Up setting, referring to the motion of a typical treadle-based wah pedal.
Produced from July 1978 until May 1987.
The TW-1 Touch Wah had 3 different font/name designs. The first release was labelled "Touch Wah" with a long dash in the TW-1. These are the rarest version of the pedal as the name was shortened to T Wah not long into the pedals lifespan. The first "T Wah" label was a smaller font than most Boss pedals, and was changed to a larger font for the remainder of the production period.