"Eine Schwalbe macht noch keinen Sommer", the saying goes (one swallow does not a summer make), but what I just experienced is quite astonishing, given the sorry state of Neumann K870/K87 capsules of late: Tonight I installed a brand-new K870 (build date late 2012), and my jaw dropped: Both sides of the capsule are lush, reedy, frequency-balanced, with a full-figured bass, and are extraordinarily musical. Only the very best K67 from the mid 1960s (the famous 'fibre board' model) could hold a candle to this one. This capsule was so exquisite and similar on both sides (very rare, for any LD dual-membrane capsule, from any period) that I still don't know which of the two sides to make the front side for cardioid operation.I am hoping and praying that this is a trend, and will report what the next new K870 capsule portends.Disclaimer: the electronics of the U87Ai which I installed the capsule in are heavily modified; so while this capsule could mitigate some of the stock U87Ai's electronic compromises (which I find especially unsatisfying since circuit diagram 05), it cannot overcome them all.
I've never heard a re-skinned Neumann capsule that actually approached the sound of a good Neumann. I've heard one of Mr. Thiersch's excellent M7-style rebuilds, and it sounded to my ear very much like Thiersch's excellent new capsules, but (especially being the Mylar version) it did not sound exactly like a good vintage Berlin M7.
Then what hope is there for a U47 owner who needs an M7 replacement?
China may be an answer to reproducing PVC capsule diaphrams. They don't follow EPA or CE environmental restrictions there.
I know this thread is old, but I'm wondering if that was a one-off experience or have you experienced a general improvement in k870 capsule quality?