need advise, which is the weakest link in my audio chain

Hi all, i am new here and this is my first post.

need some opinion and advise, which gear do you think is the weakest link that i should improve/change.

i wish to have sweet sound and detail but not fatiguing

my experience on current setup not really meet my preference  :-

- a bit forward sound 

- sometime may a little dry/harsh sounding when source recording is poor

- lack of sweet top end

pre amp - bryston bp6

power amp - lexicon nt-212 (same as bryston 3bst)

speaker - spendor sp1 

cd player - marantz cd6006

dac - rega dac

tuner - yamaha t1 & sony st-sa5es

sorry for my poor english.

thank you.