Any truth to the rumors I've read on TB that the cobalt finish is more aggressive on fret wear?
I don't know how hard the alloy is - just guessing it's stainless steel with a little cobalt (so, harder than nickel) - but it is true that it has a slight texture on the surface, rather than being polished smooth. How much difference that makes long-term I can't say. For me the tone - if I choose it - overrides that.
... EB Cobalt Flats are one of the more flexible flats in the market...
Michael_t is an expert and I'm not, but I suspect that is an understatement. Speaking of the construction, unmounted (not the extra stiffness caused by tension when mounted), I believe Cobalt flats are *radically* flexible, even compared to some very popular round core rounds.
My early impressions:
Cobalt flats are spectacularly clear through-and-through, top to bottom; so far, they're in a different sonic category from other flats I've tried.
This is something I'll have to get used to: while e.g. La Bella DTF and Roto 66 have a comfortable familiarity in the tone, the Cobalts are something new to my ear. No doubt will record beautifully. Love clarity but also love comfortable familiarity, so we'll give it some time.
Chromes, for example, are like a traditional flat with some extra highs, but Cobalts are something else, it seems to me.