Converting digital headset to analogic one

Hello! :D

Some time ago I have bought a Microsoft LifeChat LX-3000 digital, USB headset. Hmm...maybe it was not the best choice, but I want to convert it into an analogic one. In theory it is simple: I only have to remove the incorporated digital-analogic analogic-digital signal converter and connect the 2 wires of the headset to 2 Jack 3.5mm, one for the microphone and one for the speakers. Reason: my laptop's sound card is much better than the headset's built-in one.

I am pretty sure that this converter is located in the volume control box:

But things may not be as easy as they seem. Or are they?

As far as I have heard, the cable from the volume control unit and the headset consists in 2 wires. The cable of my old cheap analogic headset consists in 2 wires too. It shouldn't be complicated: the microphone wire get tied with the microphone wire and the speakers wire get tied with the speakers wire. But when I opened the old cheap analogic headset I noticed that each of the 2 wires branches out in 2 respectively 3 separate wires when they reach the headset: a blue one, a red one, a yellow one, a green one and a blue-yellow one. This is quite strange, isn't it? Or...do I have to worry about that?; should I simply tie the 4 wires together - old&cheap analogic speaker wire with LifeChat's speaker wire and old&cheap analogic microphone wire with LifeChat's microphone wire? I don't want to do somethig wrong.^^

Thanks in advance. :)

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mitzoc (author) 7 years ago
Anybody? gmoon? :(
gmoon mitzoc7 years ago
Sorry--if you don't use the "reply" button (at the bottom right of someone's msg), they may not see it when you bump the topic...

So--based on your feb 14 post, have you connected them to a a TRS plug? Tip to one headphone speaker, ring to the other speaker, shaft to the ground...
mitzoc (author)  gmoon7 years ago
Wow, I really did it!

Thanks a lot, gmoon! Now it only needs a few adjustments. A better connection is required, as the signal is losing from time to time.
gmoon mitzoc7 years ago
Cool--glad it worked!

You just successfully debugged and hacked your first electronic device. No stopping you now...
gmoon gmoon7 years ago
Oh--and buy a soldering iron. ;-)
mitzoc (author) 7 years ago

I did how u said. One wire was the ground one (the ground of the headphones, not the ground that comes together with the green wire of the microphone). The other wire was the blue one. I heard a crackle in the left headphone. When I connected the red wire, I heard the crackle in the right headphone.

Hmm...what would that mean? That I have now a fully functional analogic  headset, that only needs 2 TRS connenctors (and a small volume controll unit)?
mitzoc (author) 7 years ago
Hmm... so I should connect a 3 V battery...but to which wires? Or should I connect it to the TRS connectors? ...and, would a 9V battery be too much and definately damage the headphones?

And...when I connect the battery, will I hear a crackling noise in the headphones? An instant noise or will the noise persist, until I take the battery out from the circuit?

Many thanks for your help. :)
gmoon mitzoc7 years ago
Disconnect the headphones from your current TRS connectors (the current wiring isn't correct anyway.)

I don't know which wires to connect--that's the challenge, to find the correct connections. One will be a ground that's common to both sides--my bet is that the bare copper shield is that GND wire...

Use a single 1.5V cell, instead of the 3V. I just tried it with a pair of analog headphones and the crackle is obvious. Yes, I think a 9V cell is too much.

The noise will be "instant" when you connect and disconnect the battery. It won't persist, and you might damage the phones if you leave the battery connected for long. Just quickly make-and-break the connection.
mitzoc (author) 7 years ago
Ok, the work proceeded. But it didn't have a happy end. :(

I sectioned the LifeChat Headset's wire (between the headphones and the digital-analog&analog-digital converter) and it is identical to the wire of my cheap analogic headset. A perfect match. So I just tied the wires together: red wire with red wire, blue wire with blue wire and so on. But when I plugged in the 2 TRS connectors, I could hear no sound. And the microphone was not functioning either. :'(

I don't know where the problem may lay: bad connection (I might have not tied the wires well), short circuit (I might have damaged the insulation of some wires), different materials (the metal of LifeChat's wire is different from the metal of the cheap analogic headset, I suppose) or more seriously, what I did is a stupid thing which nobody does (some things are not to be mixed together). So feel free to laugh at me.

Some photos:

gmoon mitzoc7 years ago
No one is laughing.

Unfortunately, there's no wire coloring standard. Just connecting red-to-red, blue-to-blue, etc. is no guarantee.

I'd suggest you test the headphone wiring. Use a 3V battery, carefully connecting it momentarily, then severing the connection (headphones will only respond to DC voltage when you make or break the connection. Leaving the DC connected for long could cause damage.) You should hear a crackle, once you stumble on the right wires.

Buy some alligator-clip jumpers for this purpose.

There's at least a 50-50 chance the bare copper shield wire is the ground (-) for the headphones.

All this assumes that there is no active circuitry within the headphones themselves (which I intimated before: "We can't know if there's any circuitry in the Lifechat cans beyond the control box"-- "cans" being each ear cup.)
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