I have a 2013 Jazz Bass American Deluxe 5 string. The preamp is making a buzzing noise so it has to be replaced. When I switch to passive mode the noise disappears. I've read that others have had their Fender preamps fail too so I don't want to get another Fender preamp. It seems most everyone likes the Sadowsky preamps so I am leaning in that direction. Two questions: 1. Does the Sadowsky onboard preamp work for both 4 and 5 strings? 2. Are any physical modifications of the bass required or is it a simple swap? Audere says their preamp is a simple swap so I am considering the Audere too. I welcome any feedback on any of the brands. Thanks.