I have got my Fender Jazz running the way I want with Dimarzio Ultra Jazz pu's. I would like to retain the tones I get with the passive electronics, but also be able to adjust it more, so my question is what preamp retains the best natural tone when flat, but let's you add? A bypass might be the best way, but will that effect volume levels much? I've seen Aguilar, Audere, Bartolini, and I'm sure there are several others out there. What do you suggest?