The other colors are just plain copper. I think I figured it out after a few tries. Green is left positive, copper negative, while Red is right negative, copper positive.
I first tried using a lighter to burn off the isolation, but that just ended up burning the wire itself making it very weak and hard to deal with. The wire itself is already very thin. Then I tried just using the iron and letting it burn off the isolation by leaving it on for a minute or so. This worked better and you can tell its ready when the solder starts to stick to the wire.
So after this experiment, I found that I was right; the stock cable sucks (in comparison to my silver plated copper wire). Switching back and forth, I found the stock cable to be un-involving and less musical in general. I felt like I had to concentrate and "listen harder" for details that I could easily hear with my spc cable. I find myself having to turn the volume knob up just to compensate for the loss. Stock cable sounded less airy, more congested/muddy, and in some ways more peaky, less smooth and coherent. The sounds coming out of it were portrayed as loose, flat, with less definition and dynamics. Making it appear dull and a less enjoyable overall experience.
A perfect example is listening to Diana Krall's Fly Me To The Moon, a song that I am pretty familiar with. With the stock cable, I have never been so bored listening to that song ever.
My final opinion of the stock cable is that it really does not compliment the HD650 at all. In fact, it detracts from the performance of the HD650. I find that even a stock Grado cable sounds more transparent than this crap and is built better too. That is my 2 cents.
I agree to the 2nd part of that statement. If deciding on upgrading the cable, I would definitely go with a balanced cable with single ended adapter. If having to pick whether to choose a balanced stock cable or a upgraded single ended cable. I think I would still choose balanced stock cable, just because going balanced helps take away that veiled effect and you get somewhat of a faster signature with less congestion and more air/space around instruments. Still a better cable will add upon by improving dynamic range and better definition. So it is kinda 50/50.