Mic Bias

  • 1
  • Question
  • Updated 5 years ago
  • Answered
Can someone tell me how much voltage is applied when the mic bias is turned on?


Is it applied to both the front and rear mic inputs or is it just on the foster plug connection on the front panel?

Photo of Greg


  • 656 Posts
  • 63 Reply Likes

Posted 5 years ago

  • 1
Photo of Dudley - WA5QPZ

Dudley - WA5QPZ

  • 212 Posts
  • 45 Reply Likes
Official Response

Quote from Gerald,

Bias is only available on the front panel microphone connector. The XLR/TRS does NOT have any bias connection.

There are two sources for Bias on the 8-pin Foster connector:
There is an always on 5V sourced through a 560 Ohm resistor to pin-2 as shown below.
You can also turn on the Mic Bias in the GUI that turns on a 2.97V source that is applied to pin-8, which is the microphone hot lead.

Hope that helps