The U 89 was introduced ~15 years later than the original fet 80-series microphones, and its output circuitry differs considerably from theirs. One result is that it is available only in a 150 Ohm version, with no alternative "strapping" arrangement for the secondary winding of its transformer. But no pad resistors are used, unlike the 150 Ohm settings of the earlier fet 80 microphones--by 1980 Mr. Temmer's concerns about overloading the inputs of mixing desks designed for dynamic microphones had probably diminished. So there's no tweaking to be done there.
--best regards