Amp or phono pre + pre for better sound?

Ok, I am trying to decide whether to get the Accuphase A-65 amp first or the C-2420 pre + C-27 first from my dealer. I can't afford all 3 units at once. Which unit would make the most positive difference in sound?

Currently I am using the Bryston amp (4BSST) and Bryston preamp (BP6P)

I know this is a compromise, but it's the best i can do...

JBL S4700 speakers.

My system is displayed here in that part of the forum under "Done for Now."

Thanks for your time and help!