Headset Wiring Issues!

ranjam

New member
Help! While I know this ain't exactly 'recording' related, I don't have many other folks to ask :o. Here's the deal; I have an AKG C520L wireless condenser headset, with a 3-pin mini XLR connector. Thinking I could use it with a Shure T4N-CA transmitter, the first thing I see is that the Shure unit uses a 4-pin connector. Hey, no biggie; my music store sell an official Shure WA333-TA4F connector (are you with me so far?). Now begins the fun. The AKG headset end is molded on, so I go right ahead and chop the sucker off :eek:. Now, open the Shure instructions.......... drum roll, please.....................
@#$%!!!!!
What the heck is this? Two wires to the AKG headset; red and white. And a shield. The Shure schematic shows different colors and a wiring scheme that makes no sense. Then I ask the music store. I get the following 'instructions';

Pin 1: Shield
Pin 2: Bias (+5Vdc)
Pin 3: Audio
Pin 4: Bias return - 20 k Ohm resistor to ground or equivalent active bias
management circuit (jumpered to pin 3 when used with most condenser
microphones)​

I have tried various combinations with the red and white wire; white as 'hot' and red as 'hot'. No resistor, no bias voltage. As a simple two-wire-plus-shield wiring job(?), nothing seems to work. Sooooooooooooooooo, at the risk of having everyone kick my ass, now what the heck am I supposed to do? Chalk it up to experience?
 

dgatwood

is out. Leave a message.
Help! While I know this ain't exactly 'recording' related, I don't have many other folks to ask :o. Here's the deal; I have an AKG C520L wireless condenser headset, with a 3-pin mini XLR connector. Thinking I could use it with a Shure T4N-CA transmitter, the first thing I see is that the Shure unit uses a 4-pin connector. Hey, no biggie; my music store sell an official Shure WA333-TA4F connector (are you with me so far?). Now begins the fun. The AKG headset end is molded on, so I go right ahead and chop the sucker off :eek:. Now, open the Shure instructions.......... drum roll, please.....................
@#$%!!!!!
What the heck is this? Two wires to the AKG headset; red and white. And a shield. The Shure schematic shows different colors and a wiring scheme that makes no sense. Then I ask the music store. I get the following 'instructions';

Pin 1: Shield
Pin 2: Bias (+5Vdc)
Pin 3: Audio
Pin 4: Bias return - 20 k Ohm resistor to ground or equivalent active bias
management circuit (jumpered to pin 3 when used with most condenser
microphones)​

I have tried various combinations with the red and white wire; white as 'hot' and red as 'hot'. No resistor, no bias voltage. As a simple two-wire-plus-shield wiring job(?), nothing seems to work. Sooooooooooooooooo, at the risk of having everyone kick my ass, now what the heck am I supposed to do? Chalk it up to experience?

If the following is correct:

http://media.zzounds.com/media/wirelessfaq-4eb34d59db40d65d0b34a279f72ed121.pdf

then the right answer is connect pins 2 and 4 on the 4-pin connector together and hook them to both the white and red wires. Then take a small DC blocking capacitor and hook one end to pin 3 and the other end to the bundle of wires you connected together earlier. Finally, connect the shields together.

That said, I'm not at all certain about this, and my gut says that this is probably completely wrong; I get the impression from AKG's site that this is a proper balanced output that uses phantom power, in which case you should connect either the white or red wire to the blocking cap (but not both), jumper pins 2 and 4 together, and hook up two 6.81k resistors---one between pin 2 and the white wire, the other between pin 2 and the red wire. In other words, provide power on both, and hook one to the audio input through a DC blocking cap. Possibly provide a 100k resistor (or something) from the unused white or red wire to ground.

One other note: the AKG mic prefers a 9V-52V phantom supply, while that Shure pack only provides a 5V supply. It might work with reduced headroom or it might not work at all. It's hard to say.
 

ranjam

New member
Man, you couldn't fit an idea into the casing, never mind resistors or capacitors. I may just break down and pay a shop to do it. If I screwed this up, it's a $200 lesson. But I've spent more on getting an education, which obviously hasn't helped so far. Note to self; try to find out why I have absolutely no fear in tearing something I just brought home apart only to find I really don't know what the fuck I'm doing.
 

dgatwood

is out. Leave a message.
Man, you couldn't fit an idea into the casing, never mind resistors or capacitors. I may just break down and pay a shop to do it. If I screwed this up, it's a $200 lesson. But I've spent more on getting an education, which obviously hasn't helped so far. Note to self; try to find out why I have absolutely no fear in tearing something I just brought home apart only to find I really don't know what the fuck I'm doing.

Into the casing? You're not thinking of doing this inside a device, are you? You need to bite the bullet and buy a proper 4-pin mini-XLR connector and 3-pin mini-XLR connector and wire up a custom cable. If you do that, you should have all the room you need. Put the resistors at one end and the cap t the other. If that's still too tight, get a tiny project box and wire it up in the middle of the adapter cable. Be sure to use a strain relief.
 
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