Sorry. I didn't realize you only had 1 actual cable. Since were are talking about IC's I just naturally thought one pair. You definitely did the right thing by listening to it and confirming a difference. There's only one thing left for your to do: Chop! Have fun, just watch your fingers.
One last thing. If you are planning to use the 2 original factory terminated RCA terminals, make sure that use use them in the exact same application. For example, if you make a pair of IC's, you'll have to add a connector to each piece. When you use the cable run the like RCA's together and not at opposite ends. Needless to say, if you make more than 1 pair, keep the originals together in 1 pair. Anyway, I'm sure you would have figured all this out yourself, but it doesn't hurt to be careful.
One last thing. If you are planning to use the 2 original factory terminated RCA terminals, make sure that use use them in the exact same application. For example, if you make a pair of IC's, you'll have to add a connector to each piece. When you use the cable run the like RCA's together and not at opposite ends. Needless to say, if you make more than 1 pair, keep the originals together in 1 pair. Anyway, I'm sure you would have figured all this out yourself, but it doesn't hurt to be careful.