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Thread ID: 34310 2003-06-09 10:41:00 OT- Fixing Microphone somebody (208) Press F1
Post ID Timestamp Content User
151283 2003-06-09 10:41:00 Help. I need help fixing a Roland DR-20 Hypercardoid Dynamic Microphone.

We have had to replace the "socket" in the bottom of it (where the XLR cable goes into it), however we do not know which wire goes where.

There is a red and a blue wire. They have to be soldered onto a 3-pin XLR (Cannon) plug. Does anyone know which pin they might go to?
somebody (208)
151284 2003-06-09 10:56:00 "Two's hot, Three's not" - so red to 2, 3 to blue ! :| wuppo (41)
151285 2003-06-09 20:21:00 Dynamic microphone are not really polarized, it would if you have stereo microphones, just try it. E.ric (351)
151286 2003-06-09 20:57:00 Thanks wuppo. Do I just leave Pin1 disconnected? somebody (208)
151287 2003-06-09 21:07:00 Pin 1 is earth / shield - if the mic housing is metal, it should connect to it - you may or may not have some sort of earthing mechanism (spring clip, or wire etc). wuppo (41)
151288 2003-06-09 23:18:00 Just please dont do a Peavy and fly in the face of everyone else and apply the same rules to the wiring of speaker cables....

.Chris
Chris (3346)
151289 2003-06-10 04:28:00 Thanks Wuppo. The mic housing is metal, however there isn't any mechanism which connects it to the case. I'll have to devise one then :D somebody (208)
151290 2003-06-10 05:11:00 Ok... here's what i've done.

I've connected the blue wire to pin3, the red wire to pin2, and i've connected pin1 to the little bit of metal which connects to a screw which connects to the housing.

Now I've just got to test it...

Also, I forgot to point out that the mic appears to use Phantom power, as it has a small transformer inside it. Does this affect the wiring?
somebody (208)
151291 2003-06-10 05:16:00 If the manufacturer didn't connect the shell to anything, I wouldn't. ;-)

It's common to have a screen connected at one end of a cable only, because there could easily be "funny" mains wiring in sound systems. In such cases it's nicest not to have the metal mic case connected to the "earth" of one piece of equipment, when it might be close to the "earth" of another bit of gear at a different voltage. Even if it's not lethal, you often get hum.
Graham L (2)
151292 2003-06-10 05:21:00 No, phantom power has the same voltage on both pins 2 and 3 with respect to pin one, i.e there is no DC voltage difference between pins 2 and 3, only between 2 and 1 or 3 and 1. If there is only a transformer inside, it is probably just impedance matching - phantom power is used to drive an active circuit such as a pre-amp etc. :| wuppo (41)
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