What do you think of the DIY Cat 5 speaker cables

CAT5 is not made for audio. It is made for telephone/network. I would avoid it and would certainly never modify an amp to accomodate it.

I braided up a pair of biwire Cat5's...BIG improvement over what I had, though admittedly I was starting from a pretty basic cable. When I first tried them out I sat back with a "whoa, what's this". Until then I didn't put much stock in the cable craze...now I'm a bit more 'open minded'.

I run a McCormack DNA-1 & no issues with the capacitance. I asked Steve M about the DNA-1 stability with highly capacitive loads...he said "if there's a problem you'll know right away"...something about a blood-curdling howl....there wasn't & it didn't.

I also recent spun up eight of VH's silver IC's(various systems)..VERY VERY NICE.
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There are some good speaker cables already out there. Try them.