HI George. not sure of the colour of the mic sorry, I did know at the time but it was a couple of months back. Is the Nagra SD not the recorder being discussed here or is it something newer than the SD? tried all sorts of gain settings from low to high, also tried adjusting the headphone output, same result. was recording in a quiet room to analyse background hiss without too many external sounds. I also heard a wildlife recording on a website which exhibited the same sort of noise problem. happy to be toldotherwise though if there are better samples available in a dead room.