scootermafia
MOT: Double Helix Cables
- Joined
- Nov 24, 2008
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I figured I'd offer some advice on how to deal with the fun task of putting these plugs on. I think more people would DIY headphone cables if these plugs weren't so unpleasant, or maybe I'm wrong...in any case if you're thinking of building a Sennheiser cable or just want some tips, this tutorial will help you fix problems that happen along the way (solder bridges, how to fit in big wires) and get the plugs on.
1. Strip & tin the wire ends so that when they're inside the pin cup of the Cardas plug, they stick out about 1-1.5mm or so. Twist the wire strands tight and rub flux onto them, tin, then rub more flux.
2. Rub plenty of flux (I like to use makeup applicators, Target sells big packs of them, they work well without absorbing the flux too much) onto and around the solder cups of the connector.
TIP: So, your wire is too big to go all the way through, no problem. Simply hit the strain relief/wire entry hole of the connector with some low heat from your heat gun for a few seconds to soften it. Insert nail scissors through the strain relief and entry hole of the connector and expand the strain relief horizontally, then vertically, then horizontally, then quickly slip your wires in, and let things cool. You can take the wires out and do whatever, you've now enlarged it. This probably won't work with Jena 18g. In this case, simply trim off the strain relief and cut away the entry hole until your wires have a place to sit.
TIP: So you have wire with PE insulation (Jena, TWCu, ALO SXC) that melts like crazy when you're trying to do this delicate job, fouling up your plans as it turns into a gooey mess. Well, slip 0.5" of 1/8" heatshrink onto the tinned wire to cover the insulation at the end, apply heat from the heat gun, problem solved.
3. Once everything is fluxed up, slide the wires into the cups. Use a clip stand to hold the connector horizontal left-right and so you're looking down at the top of the connector, this seems easiest to me. Tin your iron and approach the joint from the outside of the cup, not the inside and start flowing on solder...you want to make sure that there's solder on both the wire and the outside of the cup itself ideally. This is very easy with thick wire (Jena 18g barely fits, just don't tin the wire before you shove it in if you want to ever get it in). Just go in little doses of heat and let things cool as often as possible - definitely have your clip stand holding the cable body not the end of the connector, as when it heats up you will squish an impression into the plug and deform it. Above all, watch your hand position like a hawk at all times to make sure you are not touching your iron to the plastic shell of the connector if at all possible.
TIP: So you've screwed up. There's now solder connecting the two pins somehow, you were overzealous with the solder, your hand slipped, whatever. There is a way to fix this, and I just figured it out. Attempting to dip the iron into the goo in between is fruitless, the gooey solder is not going to simply go away. And if you can maneuver desoldering braid in there and suck it up, good luck with that. A desoldering pump might work, but there's an easier way to quickly fix this if you don't have one. Get some teflon piping (I have some 3/8" if you want to fashion a crude tool with this, send me a PM) from Mcmaster Carr and cut a 0.5" thick strip of it off. This will not melt easily, let me tell you. Heat up the offending goo, then maneuver your soldering iron over one of the pins so that just the tip is in the goo keeping it liquid. Then, simply shove the teflon tool you've made in between the pins, and the solder will leap onto each pin. A winner is you. Trust me, this really works...most soldering irons even at the best of times cannot melt the Teflon. In any case, a good iron like the Metcal SP200 is easier to handle than cheaper ones for this sort of work.
4. Check for continuity between the pins although it should be obvious if you did it right. Mix up some of the strongest epoxy you can find, and put it into the cup area until it's full, then apply it to the tines of the strain relief, really anywhere around there that you think might help. Let it dry for as long as possible, an hour or two is ideal.
5. Here's how to make things not look like ass. Take some thin-wall (this eBay guy sells these packs of 12" pieces of 1/4" heatshrink that I like the consistency of) regular black heatshrink, and cut two same size pieces that will cover slightly past the end of the strain relief of the plug. Use pliers to overexpand the heatshrink, needle nose works good. Then, slide it on, it will now fit over the plug (which usually requires 3/8" heatshrink, which doesn't look as good). Shrink with the heat gun and you are done, for best results let it set another 24 hours before sticking it in anywhere. Hopefully you have done this part first - then you can simply label the 2 ground wires on the other end (the big pins on the Cardas plugs are the grounds, small pins the signal) and the right wire (red = right). This is probably the easiest way to get a cable done.
TIP: For the right/left plugs face the solder contacts of the plugs inward from the y-split, so you don't have to twist the earcup wires to get them into the headphones. Facing inward is the natural orientation, of course.
If anyone knows something I don't know, feel free to add your own tips, this is by no means the final word on how to do this annoying task. We all have our own special techniques to make this less painful.
1. Strip & tin the wire ends so that when they're inside the pin cup of the Cardas plug, they stick out about 1-1.5mm or so. Twist the wire strands tight and rub flux onto them, tin, then rub more flux.
2. Rub plenty of flux (I like to use makeup applicators, Target sells big packs of them, they work well without absorbing the flux too much) onto and around the solder cups of the connector.
TIP: So, your wire is too big to go all the way through, no problem. Simply hit the strain relief/wire entry hole of the connector with some low heat from your heat gun for a few seconds to soften it. Insert nail scissors through the strain relief and entry hole of the connector and expand the strain relief horizontally, then vertically, then horizontally, then quickly slip your wires in, and let things cool. You can take the wires out and do whatever, you've now enlarged it. This probably won't work with Jena 18g. In this case, simply trim off the strain relief and cut away the entry hole until your wires have a place to sit.
TIP: So you have wire with PE insulation (Jena, TWCu, ALO SXC) that melts like crazy when you're trying to do this delicate job, fouling up your plans as it turns into a gooey mess. Well, slip 0.5" of 1/8" heatshrink onto the tinned wire to cover the insulation at the end, apply heat from the heat gun, problem solved.
3. Once everything is fluxed up, slide the wires into the cups. Use a clip stand to hold the connector horizontal left-right and so you're looking down at the top of the connector, this seems easiest to me. Tin your iron and approach the joint from the outside of the cup, not the inside and start flowing on solder...you want to make sure that there's solder on both the wire and the outside of the cup itself ideally. This is very easy with thick wire (Jena 18g barely fits, just don't tin the wire before you shove it in if you want to ever get it in). Just go in little doses of heat and let things cool as often as possible - definitely have your clip stand holding the cable body not the end of the connector, as when it heats up you will squish an impression into the plug and deform it. Above all, watch your hand position like a hawk at all times to make sure you are not touching your iron to the plastic shell of the connector if at all possible.
TIP: So you've screwed up. There's now solder connecting the two pins somehow, you were overzealous with the solder, your hand slipped, whatever. There is a way to fix this, and I just figured it out. Attempting to dip the iron into the goo in between is fruitless, the gooey solder is not going to simply go away. And if you can maneuver desoldering braid in there and suck it up, good luck with that. A desoldering pump might work, but there's an easier way to quickly fix this if you don't have one. Get some teflon piping (I have some 3/8" if you want to fashion a crude tool with this, send me a PM) from Mcmaster Carr and cut a 0.5" thick strip of it off. This will not melt easily, let me tell you. Heat up the offending goo, then maneuver your soldering iron over one of the pins so that just the tip is in the goo keeping it liquid. Then, simply shove the teflon tool you've made in between the pins, and the solder will leap onto each pin. A winner is you. Trust me, this really works...most soldering irons even at the best of times cannot melt the Teflon. In any case, a good iron like the Metcal SP200 is easier to handle than cheaper ones for this sort of work.
4. Check for continuity between the pins although it should be obvious if you did it right. Mix up some of the strongest epoxy you can find, and put it into the cup area until it's full, then apply it to the tines of the strain relief, really anywhere around there that you think might help. Let it dry for as long as possible, an hour or two is ideal.
5. Here's how to make things not look like ass. Take some thin-wall (this eBay guy sells these packs of 12" pieces of 1/4" heatshrink that I like the consistency of) regular black heatshrink, and cut two same size pieces that will cover slightly past the end of the strain relief of the plug. Use pliers to overexpand the heatshrink, needle nose works good. Then, slide it on, it will now fit over the plug (which usually requires 3/8" heatshrink, which doesn't look as good). Shrink with the heat gun and you are done, for best results let it set another 24 hours before sticking it in anywhere. Hopefully you have done this part first - then you can simply label the 2 ground wires on the other end (the big pins on the Cardas plugs are the grounds, small pins the signal) and the right wire (red = right). This is probably the easiest way to get a cable done.
TIP: For the right/left plugs face the solder contacts of the plugs inward from the y-split, so you don't have to twist the earcup wires to get them into the headphones. Facing inward is the natural orientation, of course.
If anyone knows something I don't know, feel free to add your own tips, this is by no means the final word on how to do this annoying task. We all have our own special techniques to make this less painful.
