I have not heard the Hidiamond ic's, but do have both the Hidiamond 8 and High Fidelity Enhanced speaker cables. As I touched on in the HF thread, although my system was very satifying musically, interest in the HF cable was piqued by the number of comments in mag reviews, Audiogon threads, and a conversation with Rick Schultz, especially in creating a full loom. Interconnects are CT-1's, power cords HD 3's. The HD cable has approx. 200 hours on them, not yet fully broken in per the distributor. He suggests 100's, and possibly 1000 hours before they perform at their best.
The HF's have less than 60 hours, also well below the recommended break-in, but I am compelled to offer some noticeable observations. Break-in of both cables has been slow-going, and therefore, unpleasant. I run a tube amp necessitating shut down at end of listening sessions. Limited to three to five hours each evening, obtaining 500 hundred hours will take well over 4 months.
The Hidiamonds' stand-out, I believe, is in the density of mid to deep bass, making the music very involving. I notice no lack of detail or body. Listening is never fatiguing.
As pleasing as the HD's are the High Fidelity's, I find, offer a clearer, more open presentation. I don't know if it is due to less distortion, but the immediacy, timbre, instrument location, decay, depth and width of staging and imaging, delineation, bass response; and consequently, a rightness is what I hear. The full loom HF cables, in comparison seem to add nothing to the source material. What the limitations of my analog rig and speakers bring to each recording is transparent in ways I am unaccustomed to. With well recorded pressings, instruments, voices, background sounds, applause are more convincing. The bass is very quick and deep, but not quite as visceral. The bass is far from anemic. I still experience a growl from the woofer, but with less exaggeration. It proposes possible added distortions with my previously owned cables. The ceramic mid-range driver of the Avalon has more often than not left the mid-frequency a bit dry, but this cable offers a very palateable contribution to voices, horns and strings.
I am anticipating the changes yet to come from the HF, and although I am pleasantly impressed with what they are already doing I from time to time yearn for the deep, emotional involvement, which has been slightly thinned out. No fireworks and no artificial tuning. As, Rick has more than once suggested, I need to be patient as the system evolves.
Admittedly, this does not address the ic comparison, but may offer some insight from a fan of both cables.