The DarkVoice specifications are for 32-600 ohm headphones, as an OTL driving 13 ohms it seems probable the AEON is out of its power band. No disrespect to the product, it's just likely a poor match for this headphone. Some OTL amps aren't optimized for lower impedances, one exception I know of being the ZOTL amps, which I use, they're perfectly fine.
Yes, the Axios is really expensive. I want to be perfectly clear I wouldn't recommend it to most people either as a value or as appropriate to their systems, but there are reasons I would and do recommend them (or consideration of other premium cables).
First, it'd be remiss to not state there are many who think any upgraded cables are hogwash, overpriced or overhyped. I used to be a cable skeptic (I could hear a difference but couldn't justify the price) until my systems and headphones became resolving enough that cable changes became pretty apparent to me. I don't care if everyone agrees with me or believe me, it's a free planet and that's your right, and I understand. I also understand why some people will never buy a premium cable even if they could hear a difference. Further, I always say that while cables can make a difference in a system they are best considered a finishing touch when you have your system where you want it first.
So, why do I recommend premium cables? First is I do feel that many good ones can improve the resolution of a good system, and that some cables can create a more holographic effect, and that is why I invested in so many different high end systems. A system is a sum of its components and weak links can become more apparent, so for me I've upgraded all interconnects and headphone cables. For many systems I think DUM and DUMMER are sufficient but if your system is where you want it, a cable upgrade can offer sonic AND aesthetic differences. Reducing cables to just "price performance" misses a variable that some value highly and others set at zero.
I have the copper, silver copper, and silver cables and really like them a lot with pretty much anything I connect them to sonically. Also the silver has a LOT of silver in it, these are beefy cables. The silver can be a bit much if the gear is bright or analytical, but on my WA 5 with an Yggy it has a dimensionality that is rather jaw dropping. I'll have the WA 5 with me at the SoCal CanJam and I'll bring a few cables, so skeptics can listen and tell me they can't hear a difference.
Is the Kimber better than the WyWires Platinum? I wouldn't try to answer, they work great with our headphones and have a tremendous clarity. We sell the WyWires because I think they hit all the right notes at a price that's rational in the context of most systems our customers use with AEON and especially relative to an ETHER, and the Kimber are sold through the kind of stores that sell the TOTL gear and you can hear, test and judge for yourself. But I have always been clear, before you invest in any cables beyond our stock, invest in the DAC and amp you really want. Cables are a finishing touch, and
But when it comes to build quality and aesthetic the Kimber are just superb, and I think they make my great systems look as great as they sound. The WyWIres are functional and look really good, DUM and DUMMER look quality, but the Kimber's are drool-grade gear, gorgeous to look at and they're hand wound and built. Heck, I think they invented their weave and came up with a split that requires no housings or joints. It's craftsman work and I value things of beauty that are hand made for more than just what they do, I love that there are people who do beautiful hand work, and support their making a living doing something of of beauty.
So to conclude a bloody long answer; for people who have really invested in their systems and are running gear like WA33s, vintage Cavalli gear, Eddie Current, or other great gear, and who enjoy the aesthetic as well as the sonic value of these cables these are certainly worth checking out, they sound great, they're beautiful, and I think that's a great compliment to a great system. Could you buy a premium cable that sounds as good and costs less? I don't know and won't answer, I'm sure others will. I'm glad to have both in my collection, use and enjoy them both, and sell the WyWires because they are great products we feel are a worthy upgrade if you are the type who considers that to be of value.