Best place to connect phono preamp to Fisher 500C?

Thank you for your response. The Linn presently has a Trak cartridge which doesn't work with any of the inputs. I also have an original Naim setup that was purchased with the Linn. It is a NAP250 amp, NAC 42 passive preamp, and Snaps power supply. The Linn sounds great with this setup but can not compare with the Fisher and my NAD Cd player. I really prefer the tube sound. I have been experimenting with marrying the two systems, any thoughts?
Regards

I have a 4 pin DIN to RCA phono cable. I am a little unclear where to plug into the Fisher. I have been told to use the tape out on the Fisher. A little nervous, don't want to short anything out. Getting confusing, may just go with my original idea, although I am very curious, I like the idea of the seperate power supply of the Naim.

Thank you everyone for all of the excellent information! It never ceases to amaze me how much knowledge can be found in these forums. I ended up buying a seperate phono preamp and have found the gain to be excellent. Thanks again!