should i upgrade ?

ive recently been playing alot more of my old records. i have a denon dp-45f and a cambridge audio 540 preamp, playing through about a $3500 amp & speakers. most of my records are in vg+ condition, but i notice while most sound only fair through this set up some, say 1 in 5 sound great i mean 20 to 30% better. this has me wondering since my record collection is what it is, and i only buy used records when i add to it. would a better set-up bring the fair sounding records up to great? or since this system seems to play some records very well that its probably more my records than my system ? thanks for reading.

I don't know about others here, but everytime I have upgraded my system I have found that records that I thought were mediocre sounding all of a sudden sounded amazing. Granted you will still have records that no matter how good your system will still sound lousy.

Also, why don't you buy new records? There are plenty of amazing re-issues out there.