BAV199 are suitable for mike preamps like THAT 1512 but are too noisy for condensor mike stuff.? You want something like Ir 0.2pA.? There's nothing spec'd to that level as its very temp. dependent.? You just have to guess that the paper spec. is pessimistic and by experience.
?
BTW, the THAT datasheets recommend 1n4004GP.? There's some AES papers on The Phantom Menace by THAT & Wayne Kirkwood that explains the choice.
?
I don't think diodes with leakage low enough not to introduce noise to a 1G input will protect anything.? They? will be too fragile and too low Vr Reverse Voltage.? They are suitable to run FETs at Idss for something like simpleP48.
?
That's not to say they don't exist cos some must be integrated in OPAs
