You can ditch the Sansamp and get an amp you like. That, and play forward on the strings; between the pickups and the neck. That classic sound, while sounding rich and full, implying loads of low-end also has mids which is where the definition comes from. The Sansamp scoops the mids unrelentingly leaving you a sound that's OK alone, but not useful in the context of a band and not at all vintage, (unless a mic and a DI were out of phase).
I have tried and tried to make mine do something good, but the only thing it's any good for is a simple DI, i.e. turned off. I've also compared it to my Ampegs and other vintage amps and can find no relation. Even with the tone controls rolled all the way off, to try to help the mids, it still doesn't cut.
Really, adjust your playing and your then your amp, and if you record, use a mic and a good DI and mix the signals to make something good. For live, either mic an amp you like or adjust your playing to sound good direct, which is what 95% of sounds techs are going to want to do.
And there are flat wound strings - clear pitch and focused sound. They'll do wonders for your pursuit of vintage sound....