I had the same issues with an american standard/california jazz a while back, stunning bass but just to toppy for me. I tried model J pick ups to darken it, but it didnt really help. A few people suggested flatwounds to calm it down, but i sold the bass on. I now have a limelight jazz that has flatwounds and a hayman 4040 that has them on. For the sake of £22 for a set of fender flatwounds its worth a go.