Guitar Shop 101: The ABCs of Output Jacks | Premier Guitar Mar 25, 2016Guitar Shop 101: The ABCs of Output Jacks. John LeVan. March 25, 2016. A A this jack replaces the guitar’s endpin. Barrel jacks can have mono, stereo, or TRS configurations. Photo 3 shows the wiring for a stereo open jack and Photo 4 is a stereo barrel jack. Photo 3Author: John Levan wiring a 3 lug input jack | Telecaster Guitar Forum Jan 29, 2011Ive done my share of wiring but ive never wired a 3 lug jack before. ive got it all done but the jack. a p-rail from seymour duncan going into a banjo for a friend. sure if there are two i need to ground or what. info i appreciate ks!