Part of the sweetness you are hearing is the wood of your H575. Good pickups should amplify, not color the sound of a well built guitar.
Archtops made of carved/solid wood should have a nice sounding natural acoustic sound. That natural sound should be amplified through pickups (and obviously your amp of choice).
I experienced that with my former Sweet 16. Unfortunately its acoustic sound left a bit to be desired, so I went on a pickup adventure, trying out 3 different p'ups (Schaller, Gibson 57 classic and finally a custom wound Kent Armstrong 12 pole. Each pickup improved the sound...a little! The best was the KA 12 pole paf. In the end I sold the guitar and later picked up two H575's. Both of them sound amazing, no matter what pickup I put in them (Schaller, HRW, Seth Lover, etc.) I attribute the guitar's construction as the primary reason for the basic tonal sweetness. Each pickup contributed to the lows, highs and midrange...a little. My 575's sound great with or without an amp! I guess that's why I own two of the same archtop. Heritage archtops are hand made, so each has its own personality, feel and sound.
Bottom line, you got a good one!! ?