@vr1 -- Thanks for your interest in iSine20. iSine20 and iSine10 were designed from the ground up for use out of the best source you can drive them with. We designed the Cipher cable for use as a very easy to use, portable solution for those who do not wish to carry yet another brick (DAC/Amp).
Since the iSines haver close to negligible distortion even at high SPL, we felt we could take it one step further by also adding an EQ to the Cipher cable. I have posted the the EQ used in the Cipher cable in this thread and some variants. Many in this thread have also suggested their own variations to the EQ for use with android devices or through PC or MAC desktop setups.
You do not need the Cipher cable to achieve the best results, but it is a convenient option if you happen to use an iDevice. Many are also happy with iSines20 without the need for any EQ when paired with a good source. It is hard to directly compare the standard cable with the Cipher cable and deciding one is better than the other without describing the source used to drive.
Please feel free to contact me if you need a suggestion based on your setup.