Jupiter: Digi-Key doesn't sell the 36 mH inductor in small quantities, just the 33 mH and 39 mH.
Good point. They give you a great price on the 36mH but you have to buy 100 of them. So it seems the 33mH is the go.
Jupiter: Do you have the actual frequency response of the Stax SRS-4040?
No, for the simple reason that my binaural microphones aren't calibrated. Apparently some kind of plot can be found in the handbook which comes with the Stax, but without knowing exactly how it was measured it might not help at all. And if you did have an actual frequency response plot, what would you do with it? It has little meaning unless you plot other headphones on the same graph, or a target curve such as a diffuse field response.