How to make a USB soundcard
28th Mar 2010 | 08:00
Subvert a USB headset to cobble together a soundcard
Everyone has dreamt of being able to save the day by swooping in and helping that damsel in distress out, by plugging in that vital USB sound card when the sound fails on her laptop in the middle of an important product briefing. Haven't they? Just me then?
Daydream aside, the useful nugget of information we have to part with today, is that cheap throwaway USB headset you have lying at the bottom of a drawer can offer a useful life-enhancing function: working as a USB sound card.
The fact is, to connect and work via the USB it has to offer the analogue to digital conversion done by a standard sound card, along with the all important USB interface as well. This means combining the subtly of a lug hammer with a bit of crafty soldering we can easily construct a generic USB sound card with both stereo output and microphone input.
You're not going to need much more than a couple of 3.5mm mini-jack sockets, a suitable box or heatshrink to contain the thing, a little bit of wire and a soldering iron. This is a perfect little project to cut your teeth on if you've never tried soldering before.
Everything is made for you already and you just need to pick up a cheap soldering iron, usually you will be able to get a basic one for around £5, or pick up a starter kit on eBay for around £20.
What you will need
2 x 3.5mm mini-jack sockets
Suitable box or heatshrink
1. Collect a bunch of stuff roughly along these lines.
2. Our main area of attack is the box dangling off the USB connection. If you can keep it in one piece great, if not, you'll need a replacement enclosure.
3. Once open you need to establish which of the headphone wires carry which signals. The ground here is labelled 'GND' and is the unshielded copper wire. The blue and red wires carry the left and right channel audio, while the white is the microphone line.
4. With the wires identified – we literally wired up a jack and touch the wires to each terminal – you'll need to decide if you want to transfer the lot to a new box. In that case you could mount internal jacks and use a bit of breadboard to easily couple the connections, else you can cut the headset and start stripping the wire.
5. Once you've added a couple of strips of heatshrink make sure you tin the jack terminals.
6. Slip the jacket over the wire and solder the wires in place.
7. The mic and speaker port share the common ground, we soldered a wire to the ground in-wire.
8. We used two layers of heatshrink: one to cover each single wire and a larger one to cover where the split occurs and give it a little physical support.
9. If you have any affinity for your headset then you can always attach 3.5mm mini-jacks to this and keep on using it.
10. The final thing ends up looking like this. Slightly more useful than what it started off being.
First published in PC Format Issue 237
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