High end / high fidelity sound is about taking extreme care of the signal start to finish. The straight wire paradigm is used throughout the industry to achieve this. Avoid playing with the signal or making the path longer. If you want to improve the sound of your system then I would concentrate on removing any electronics that does DSP or has tone controls. I would switch back to your Sansui preamp and if that is not a great improvement then invest a couple grand in a used high end preamp. This should significantly improve your system far beyond what a turn table change will do. The preamp is the heart of any good system and is worth investing in. The results will then reflect your other components.
I highly recommend Robert Harley’s book: The Complete Guide to High End Audio to orient you to this wonderful pursuit.
I highly recommend Robert Harley’s book: The Complete Guide to High End Audio to orient you to this wonderful pursuit.