Gretsch Junior Jet_0000_13 Published October 12, 2015 at 900 × 600 in Upgrading a Gretsch Junior Jet. ← Previous Next → The black P-90’s really look the part, and sound absolutely incredible in the Mahogany body, while the new tailpiece intonates perfectly! A very worthwhile set of mods for what is no longer just a cheap beginners guitars