I have a Larrivee OM-09 from 2004. Last summer (2012) I changed the pickup system from an LR Baggs Dual Source system to the Anthem SL. I love the way it sounds, but within the past few months I've noticed that when I dig in and play harder when I'm fingerpicking the sound has a kind of flutter. Kind of like a tremolo.I don't think it's the guitar, because I've never noticed it when I'm not plugged in. And the flutter happens no matter what cables or p.a. or amp I'm running through. It's not extremely noticeable. I don't think anybody at my gigs has noticed it except me, but I'd still like to fix it. Any ideas?