I need to add a preamp to my acoustic, which has a k&k pure western in it. I am mainly looking at the K&K pure and purel xlr preamps. It seems like the big difference is the pure has the phase switch for feedback. Is this an issue for me, is feedback something the house it supposed to fix. The acoustic is only for duo stuff, so we don't play loud. In a full band setting I use my electrics.