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
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IMHO, and at the risk of telling you something you already know, once you've reached your level of components, and especially since your're not considering a speaker upgrade (and I'm not suggesting that you should consider it), the only way to tell is to demo a piece--source, amp, or otherwise--in your home w/ your equipment. Beware of assuming that a newer, more expensive component will give you an upgrade in sound.
I reccomend you get power straight first,cond,cables,ect.Every other thing after that.imho.