You might try Kimber Hero. Easy to find and you should be able to resell quickly if it doesn't work out for you.
I had a 640C for several years and found that a good powercord made a real difference. I used a VH Audio Flavor 2 with good results. Like the Hero interconnects, the VH cord is in a "real world budget" range.
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I had a 640C for several years and found that a good powercord made a real difference. I used a VH Audio Flavor 2 with good results. Like the Hero interconnects, the VH cord is in a "real world budget" range.
e