Did you see the ad that was posted today for the new MIT Z cord? The seller claims that the improvement in sound quality is so profound, that it's like you spent an additional $2-3K on your preamp, or your money back. OK, we have all heard claims like this before, but it certainly got my attention.
Have you tried your model 11 on that preamp yet? I'm a big fan of the CPCC cords. Problem is, there are so many diferent cords available that are recommended. I would stick with trying popular brands that can be bought used at good prices, and quickly re-sold at little or no loss on your investment. Some good ones to try first have already been mentioned here, and I would add the Blue Circle and JPS analog AC cord to the list. I also have tried and like the Acoustic Zen cords.