There's some good info at
http://www.headwize.com/faqs.htm...
quote:
Why can't I splice/solder/repair headphone cords from Sony (and some other brands)?
The wires in Sony headphone cords are insulated with a lacquer coating, which must be removed to make an electrical connection. Most low-wattage soldering irons are NOT hot enough to vaporize the coating. Here are some options:
- Dip the wires in alcohol and ignite with a match. The ignited alcohol should burn off the insulation. (Note: I have received email that merely heating the wires with a match or cigarette lighter (without any alcohol) works equally well.)
- Put the wires on an aspirin tablet and apply a soldering iron to the wire and aspirin until the aspirin melts. Aspirin is an acid that should dissolve the insulation.
- Try a high voltage soldering iron if available which will burn off the insulation while soldering
- Use a pocket knife to gently scrape off the insulation
- Dip the wires with a lacquer solvent until the coating dissolves
With any method involving a solvent, make sure there is adequate ventilation and avoid inhaling any vapors released by the process. After burning or dissolving the insulation, wipe the wires clean of any residue before soldering.
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