Aha. So here we go. First of all you may ask, is it worth me attacking my standard Nokia headphones and added a 3.5 mm adapter so I can use any other headphone ?. The answer clearly is yes, after doing a comparison of various headphones the sound quality of the Nokia HDS-3’s is rather awful, certainly no bass, a rather lame top end and to cap it all I find them uncomfortable.

Before we begin you may like to maybe buy another pair of Nokia HDS-3 earphones just in case something goes horribly wrong. They often pop up on Ebay costing only a few pounds.

Lets begin.

Tools.

You will need:-

1. A soldering iron. One that tapers to a sharp point.
2. Some solder
3. A small precision screwdriver. I recommend N67BG 5pcs Screwdriver kit from Maplin

http://www.maplin.co.uk/Module.aspx?ModuleNo=43408&TabID=1&source=15&WorldID=&doy=4m10

They only cost £1.99 and are nice n chunky which you will need as those screws are done up tight !. The size is 0.3 and it’s the yellow one you need.

4. You will also need a headphone splitter, this is a cheap way of getting hold of a pre-wired 3.5 female stereo socket. In fact you will have two in case you mess one up. Again Maplin can supply them priced at £3.99.

http://www.maplin.co.uk/Module.aspx?ModuleNo=43086&TabID=1&source=15&WorldID=&doy=4m10

But of course you can use any pre-wired 3.5 socket (I used the extension lead which came with my Sony Earphones as it was very thin and also gold plated.)

The Job.

5. Cut off one of the female 3.5 mm sockets and about 3” of wire from the splitter, carefully trim back about 15mm of the black outer cover, being carefully not to damage the wires inside.
6. Now twist the bare wire (-) into a single strand and add a tiny bit of solder to the end.
7. Cut off about 5mm of the cover of the red and white wires and again add some solder to the end.
8. Now unscrew the back of the Nokia HDS-3.

(Picture Image1)

9. Inside you will see a number of wires going into the base, don’t touch any of these. At the top you will see 2 wires on the left and two on the right. The markings on the PCB say L+ and L- and R+ and R-. Hold the soldering iron carefully on these points and pull the wires free.
10. Now solder on the red wire to R+, the uncoated single wire to L- or R- and then the white wire to L+.

(Picture Image2)

11. To run the cable out I recommend drilling a hole at the top of the case, make it smaller than the wire so the case will hold it tight. (See first pic below) OR as you can see from the second pic below, I ran my wire out below, although I doubt this will be possible unless you use (as I did) a very thin cable.

(Picture Image3)

(Picture Image4)

12. Now connect it up and check it is working ok. If not, maybe it is soldering incorrectly or maybe the uncoated (-) wire is touching one of the (+) wires and is shorting out.
13. Finally, if you ran the cable out through the top of the case u may like to put a dollop of super glue there to make sure it holds firm.
14. You will notice on mine, I used an old piece of cable that I ran through the original earphone cable holes and I use this a necklace holder.