I read that a low-Z mic has a low source Z, but it wants to see a high load Z. The trick with a preamp is to present a high Z to the mike, but produce minmum noise with a low-Z source.
But that's for perfectionists. A transformer will work fine. Capacitive loading at the hi-Z side will affect highs, even a few feet of coax is enough to be noticeable. So the transformer should be fairly close to the radio. Since the transformer inductance and the RF filrtering and cable capacitance will be shunting the mic, some resistive loading (10K, more or less) on the high-Z side might help the frequency response, at the expense of level. About two feet of shielded cable would allow the audio transformer to be a little bit removed from the power transformers, and might help keep hum out of it. I think Radio Shack carries audio transformers of this type. Bacon, WA3WDR ______________________________________________________________ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
