Sakahara. First, you are diplomatic in your posts on speaker cable. Thank you. I would note, however, that you seem very enthused about the Ensemble stuff, given that in posts where people ask for a cable recommendation your contribution is, invariably, "dump everything else you got and get Ensemble!" On another active cable thread I see where someone even accused you of being a shill for Ensemble dealers. I don't believe that; your are just excited.
But I think it is important to give one's opinions, especially if so stronger offered, with a recognition of context, otherwise people may get confused. This means the context of the system where the opinion derives and the context of the system that the recommendation is directed towards.
In this case, you are recommending a cable from a company, Ensemble, whose electronics and speakers have a certain sonic signature and philosophy, which I have found to be firmly allied with solid state electronics and their inherent limitations and strengths. Similarly, your EVS passive pot and Rowland Model 10 amp bear a similar solid state orientation (albeit more musical, yet still with the same harmonic and spatial limitations). On the contrary, this questioner's context is a 300B SE-based system, something that I think it is safe to assume is not Ensemble's cup of tea, so to speak. To say that Ensemble bests AudioNote Kondo cable, particularly the new stuff, in an SE-based system using AudioNote amps, strains credibility (Ensemble promotes solid state, metal dome tweeter-based systems with all components integrated and sourced from Ensemble - and their cables are tuned for that application).
Pogi, before you go with all-Ensemble, please look at the new AudioNote copper spkr cables. At $50/ft they supposedly best the old SPz - no chopped liver itself (copper line is now below the KSL line, that recently took the place of SP series, which is why you are seeing so much of it all of a sudden on the used market). You could go with NBS (Pro or higher in the classic line), but for this money why would you?. That argument also holds true for Purist.
This cable is in my second system: Sony CD player, Supratek Triode pre, NBS Pro IC's, Spendor LS3/5A speakers, Electraglide PC's, AirTight ATM300 SE amp (all hard wired, NOS tubed). I think it makes good comparison with your system and, assumably, your listening biases. In my system, it has been fully capable of staying with the horses upstream, revealing every nuance of the Ken-Rad black glass 6SN7's in the pre and WE300B's and Mullard 12AU7's in the amp, and that's saying something. Sounds of Silence distributes it. You might want to give it a listen.
(Incidentally, do the Quest SE's sufficiently drive the AE's? Just curious...)