Help with kef r900 issue


I bought a pair of kef r900 speakers from kefdirect in April 2018. I enjoy them most of the time, but with some vocals, e.g., Alan Jackson, Allison Krauss and Mary Chaplin Carpenter, at nearly any level, they sometimes make a ripping, tearing or distorted sound that is hard to describe. Initially, I used a McIntosh MC202 with 200 rms, and now a Rotel RB 1590, with identical results. Initially, I used a very old Transparent Musiclink cable and now a Transparent Plus, again with identical results. I’m about to dump these unless I can figure it out since KEF has no one in the NW to repair them and they advise against paying to ship them (I agree). Before I write them off as a bad bargain, theories are solicited! Thanks
128x128maritime51
I will disclose and demonstrate the condition. (What you don’t know is that I expressly assumed the risk that no market exists for the speakers with this condition.) If that results in no sale, Goodwill gets them and I get a deduction. Your implied assumption is false and insulting. I’d say I’m the guy who bought them without being told....

Your underlying premise, that morally I should NOT sell them to anyone is, at best, silly, and at worst, calculated to mislead, confuse the issue, or inflame others.

Do people keep cars cars they hate? Houses? Amps? Whatever?

Thanks for your kindness.

Oh, by the way, KEF denies a design or fabrication defect, from which one must infer it denies the condition, so.....
@ Mr Decibel. Before I bought the kef 900, I used the McIntosh gear with Martin Logan SL 3’s, and neither any of these recordings nor others produced this terrible sound. It started with the KEFs, and then I suspected I needed more watts, thus began the replacement of all electronics and wire, yet the condition remains. Believe whatever you want, but I’m convinced it is these speakers, and I’m done chasing them with money.

Before you ask, I sold the ML’s when the KEFs showed up, basically for salvage just so a guy would take them away, and as the condition is truly a latent one, didn’t discover it for a time until random playing of CD’s. 
I have a pair R700 with the same coaxial unit.  I noticed an issue with some female vocals for the first 200 hours or so but only on mediocre pop/rock recordings. There was a bit of a metallic etch to the voices, almost like they were distorting, but I don't hear that anymore.  I listen to classical mainly and they sound great.  Very clean with great string tone. I did notice the internal jumpers may not have made full contact as the knobs had backed off due to cabinet vibrations.  I installed jumper wires instead.  I don't know for sure if extended break-in or the jumpers solved the problem.  
@rotarius After resetting the rotaries several times, there is no change. Your description of a metallic edge is how it starts but it immediately degenerates into nothing but a harsh noise.  As you say, classical music is lovely.