ADL has been an advocate of NOT using black insulated wire. This stems from a comment by Stan Warren (the S of PS Audio) about how when he used computer rainbow colored ribbon cable for his preamps, using the black strand sounded like “Sh*t”. In his Superphon products, indeed, the black strand was always left unused. Curious, we hooked it up and the sound was terrible: muffled, murky and definitely without much detail. This was very odd as the other colors sounded ok.
Five years later, I mentioned this to a customer who was a painter. He stopped and and gave us the best explanation we had heard to date (Thanks Randy !). In the mixing of paints, black is created by adding carbon to the basic substrate. Carbon is slightly conductive and the black insulation actually becomes a poor conductor rather than a good insulator.
While there are some black pigments that do not use carbon black, the vast majority do use carbon. The black insulated wire, in comparison with other household Romex options and with using Euro color coded power cables always shows that not using black insulation adds more openness and air to the sound. Euro power cord is color coded blue, brown, green compared to the US black, white, green. Red is sometimes used in the US, primarily for switched outlets.
We worked with Jim Patrick of Music Metre about this and he eventually switched his entire product line to non black insulation using clear and white as his preferred wiring. When ADL made their own power cords using the Daletech low leakage cable, we were careful to specify the Euro color coded wire. Even with Belden power cords, the Euro coded cords have more top end extension than the US versions.
We notice Kimber is slowly moving their line up into a non black insulated configuration. The new Furutech line uses red instead of black for the hot lead on their power cords.
For home remodeling we recommend the same. Of course, convincing your electrician to do so is another thing. They will not want to run individual power lines, but you can have them run a four wire Romex, which adds a red conductor, This red lead is normally used for a switched outlet, but you can use it and still meet UL specs for exclusive use for the hot lead. Four wire Romex will add to the cost, but the cost is relatively negligible overall.
Many will not believe this, but our experience tells us this is so. All of our custom work eliminates all black insulated wire.