Which Component Needs to be Upgraded First


I need your help. I am looking to upgrade a component in my system. My question is which of the components is the weakest link and should be the first to upgrade. source: Sony 333es SACD, Pre-Amp hand built by Veda Audio - Dyna Hi Kevin Gilmore design, B&K ST 140 amp, Talon Audio Khorous-X speakers (the speakers are not going to be considered for upgrading. Thanks for your wisdom.
gunting
I would recommend that you upgrade the source first, the Sony 333es.

Cheers,
John
I thought you were going to say the B&K was a good entry level amp in its day, and that it was my weakest link. Do you feel that there would be noticeable improvement in sound with a newer moderately priced CD (source)upgrade? If so, is there a good bang for the buck model you recommend?
How about just purchasing a benchmark DAC and using the Sony CD player as a transport?