Best Copper Dig. Cable For < $300

What is the best copper digital cable for less than $500 and where can I buy it from.I'll use it with a tube DAC similar to the Altis Reference.Thank you.
I don't know where to find a copper digital cable, but why do you want copper especially? I'm using Stealth Varidig digital cables, both RCA- and XLR terminated (S/PDIF, AES/EBU), and both beat anything else I've used, including Altis Altimate optical. 30-day money-back guarantee too. Check them out, with explanation of why they're so good, at
The best copper dig cable I've used is Harmonic Technology called copper cyber link. I think I paid around $100 for it with a money back garantee. If you want one email me and I'll let you know more info.