I have a couple of the 1980s Radio Shack/Realistic PZMs that I would like to use as room mics. I love how the mics pick up sounds, but I find the frequency response to be unbearable - particularly in the upper midrange around 5-6k. I heard that the capsules and basic hardware on these early models are of much higher quality than the rest of the components, being held back by the transformer, unshielded 1/4" cable, lack of power, etc. I wonder if scrapping the transformer and building my own preamp will seriously improve the sound quality of the mic- with the aims of making it a lot more transparent and less nasally. Anyone have any experience?