I don't know if a phaser is built into every electro-acoustic, but my Crafter FX has one. However, when I changed the battery and plugged it in, the phaser, on the little control panel on the side, wouldn't switch off.. : /.

Any help?
it's not a phaser, it's to invert the phase on the signal
My Guitars:
Gibson Les Paul Studio
Epiphone AJ
Ibanez Strat Copy

Orange Tiny Terror Head
Old beaten up Peavey cab
Marshall MG30DFX