The better the copper, the better the sound.
Triple C will sound better than OCC which in turn will sound better than OFC and so on. Of course cable geometry, construction, solid core or multistrand, plus materials used for insulation and sheath play a sifnificant role also.
If making your own plenty to choose from big Japanese brands, Furutech, Nanotech, Neotech, Acoustic Revive, Oyaide (not order of preference).
