Looking at the Drake Service Manual, the TR7 engineering gang included a 470K mic input resistor between pins 1 and 4 on the mic connector.? That gives the TR7 owner the option of using it on pin 1, or excluding it on pin 4.? That's in addition to a ~150K resistor?at the base of the mic preamp transistor.??Interesting, it's not like that on the economically downsized TR5.
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Paul, W9AC
Paul Christensen