Interestingly, now he markets cables and tells his customers to use them with his electronics.
Well, we all grow professionally, don't we Like Spectral, he must have eventually realized there is exactly one set of cable characteristics (specs) for the length of cable purchased that provide the exact optimum operation, and he's even gone to the extent of using custom connectors so you won't easily use another cable. Same for the power cord, which is not detachable. That's not to say that other cables are FAR from optimum, just that they are NOT optimum. Personally, I have absolutely no problem with someone *competent* calculating the exact spec for cables for me, and I would gladly be in the minority... BTW, FMA have a couple of articles on why speaker cables must be matched exactly with their amps (here and here).
Coincidentally, someone on the net contacted me recently because he was unhappy with the higher-end MIT speaker cables he's using, and he was convinced to go "lower" to the Spectral-spec'ed 770UL Series 2 for his pair of 360's. Not surprisingly, he complained about the same issues I had identified when I auditioned the Magnum MA and other expensive ones like it (e.g. bloating, and other distortions). So what do you use for speaker cables?
I've tried a variety of gear. Goldmund (preamp and Telos amps) and Boulder. I still like the Boulder gear very much. The 101E journey began with an Accuphase preamp and first Brinkmann amps (no go), then an Audia Flight 100 camp (seemed to have restrained dynamics but very smooth). From there I tried Lamm M1.2 amps (I had previously owned M1.1s and ML1.1s on other speakers) and those were okay - bought a Boulder 1060 and tri-amped for a while. A 2060 came up, sold off the amps and that made a major difference. Actually, to get the chronology straight, I tried a Boulder preamp first, with the Lamms, and then decided to get the 1060. In the end I will have the Boulder gear on the 101s and the Spectral gear will probably move to power Piega CL90x speakers. Now I have yet to try this last set up as I have been enjoying the Spectral gear on the 101s too much to change them out.
Still running the 101Es and the 360S2 are fine for powering the speakers adequately beyond any listening level I can endure without damaging my hearing. I have Boulder gear as well and between a heavy travel schedule and reinserting the Boulder gear I've not listened to the Spectral gear on the 101Es the last 10 weeks. I'll put the system back and get back to you on what I'm hearing.