A pedal that has worked well for me with both acoustic and electric solid body applications is the Seymour Duncan Pickup Booster. It streets at about $80 bucks US and has a three position resonance switch to help single coil electrics sound fatter. However in its center position it is entirely neutral and amps up my Taylor ES system very well. 6db to 25 db. I do recommend it. True bypass switch, small footprint.
