I think the relevant patent may be the one attached here, from the USPTO's Web site. Its "adjusted expiration" date is listed on Google's patent site as June 10, 2028 and no, Google's copy of the patent document is no better than the USPTO's. It was filed in 2005 and granted in 2010.
Boy am I not a patent attorney, nor do I have time to study this unwieldy thing right now. And from what I've read on line, one or more lawsuits may have resulted in some of the claims being nullified.
-- In their suit against Røde they listed the following patents, with their dates of publication shown:
US 7,711,443 B1; // 2010
US 7,929,902 B1; // 2011
US 8,385,814 B2; // 2011
US 9,336,307 B2; // 2016
US 10,276,207 B1; // 2019
US 11,610,605 B1 // 2023
[edited later to add:] jbell, I think you're exactly right to be concerned about the preamps, specifically their dynamic range. You can use the most advanced A/D converters in the world but if the mike preamps clip, or their noise floor is exposed, you'll have nothing but a pure, pristine recording of a clipped or noisy signal. Deity claims to have a new generation mike preamp circuit that's about 10 dB quieter than the previous generation, and they say that those preamps are in the PR-4.
