NAMM '17 - PRS 509, SC 594 & J-MOD 100 John Mayer Signature Amp Demos Jason ShadrickJanuary 25, 2017VideoSee what two high-end axes—with added tonal flexiblity—sound like through a signature amp that was years in the making.whats-newjohn-mayerguitarsvideostube-headnamm-2017gear-show-demoprsgearamps6l6GearElectric GuitarsAmpsVideosNAMMReviews