T-Rex Engineering Tonebug PhaserAn Effective Phaser With Modern And Vintage Modes. The Tonebug phase shifter adds a dynamic undulating dimension to your sound. Phasers have been around since the late 60s and are instantly recognizable as a signature part of many great guitarists' sound, including Brian May and Eddie Van Halen. The T Rex Phaser gives you everything you need for a gorgeous phased sound using just two simple controls: RATE and DEPTH. And it sounds great no matter which