Mic XLR to RJ45

[M5AEO]

I want to use a microphone with an XLR plug with my Yaesu FT-897, which has an RJ45 socket.  The Yaesu end of things has two wires for the mic input, but the XLR has three.  I tried to use the red and blue wires from the XLR, connected to the  2 input wires on the Yaesu, but all I got was a loud buzz!  Does anyone know the mysteries of the XLR mic wiring?

Jonathan, M5AEO

[NR4C]

Check out the Heil  Sound web site for mic wiring diagrams.  Should find it there.  the XLR is a balanced line while your Yaesu is un-balanced.

,,,bill nr4c

[KA4POL]

Microphone wirings can be found under http://homepage.ntlworld.com/rg4wpw/date.html

[M5AEO]

Thank you both!

[AC5UP]

On a three pin XLR, pin #1 is normally ground & mic cable shield. Pins #2 and #3 connect to the microphone element. With a balanced input both sides of the microphone are equally above ground potential. In a studio setting it's important which wire goes to which pin as multiple microphones need to be phased identically, likewise if we're working with an electret mic element using phantom DC power we'd make sure the polarity at the element is correct. Otherwise, either side of a dynamic or crystal mic can be considered to be 'ground' and that's what we'll do for an unbalanced mic input... Tie pins #1 and #3 together to 'ground' then consider Pin #2 as the 'hot' lead.

http://www.scotaudio.com/wiring.htm

[KB1GTX]

On my ft857d I removed the switch on the back of the stock mic and installed a switched 1/8 phone jack which lets me use the ptt on the mic with any mic.

Currently I'm using a rode nt1a with a 36v battery pack.

[WA3SKN]

Many of the XLR types are low impedance, some have pre-amps and are designed around a 0 dBm output.  Do try and match impedances and levels, as most radios work with around a -60 dBm and 600 to 2000 ohms impedance.
So a "just match the wires" design may not work!
Good luck with the project!
73s.

-Mike.