I had a JPS Digital AC, purchased for use with my Levinson DAC. I found that it definitely had a "quieting" effect on digital. Too much of an effect, in fact. It crushed dynamics and made everything sound slow.
If this is the effect you're after, you can reproduce it yourself using a standard power cord and a ferrite core.
BTW, after reading about the alleged off-the-shelf origin of the JPS cord, I looked underneath the Techflex wrapping on my own JPS cord and verified for myself that it is indeed a repackaged OEM cord from Eupen.