Please name a type of cable, can't find a supplier not knowing what it's called. - Page 1
Forum section: electronics / beginners

author: ehler
author_rank: Newbie
timestamp: April 15, 2014, 11:24:00 am
content: I've produced a prototype of a system that is made up of several PCBs. The resulting object had to be very flexible so to join them up I stripped out some broken headphones for the core wires. The result was a great flexible joint. I think I've got the geometry and strain relief sorted out.It's a fine stranded flexible cable, coated like magnet wire with reinforcing strands of something like nylon. A typical headphone cable has three or four strands of the stuff. (Photo attached).My problem is I'd like to buy it by the reel but without knowing what to call it I can't find it. As much as I google I can't get past assembled headphones or headphone extenders/adapters etc.Can anyone help me find the stranded wire that goes into a headphone cable?My google-fu has failed me.

author: Simon
author_rank: Unknown
timestamp: April 15, 2014, 11:26:52 am
content: I thought that suff was horibe to work with. Last time i reid to redo the plug on headphones the wire was so bad I could not solder to it.What is wrong with standard hookup wire, something like 26AWG in 7 strands is quite flexible.

author: Jon86
author_rank: Frequent Contributor
timestamp: April 15, 2014, 11:28:00 am
content: Quote from: Simon on April 15, 2014, 11:26:52 amAgreed, it's pretty disgusting cable.

author: ehler
author_rank: Newbie
timestamp: April 15, 2014, 11:36:52 am
content: thanks for the replies.Although it was a bit of a pain to solder down, once it's there it is just that bit more flexible than hookup wire and much less bulky without the outer insulator required. I need to get three conductors down a 2mm gap between boards. Hookup wire is just that bit more springy and seems to have a bit of a memory for the bends you put in it.Single strand magnet wire is not quite as soft and forgiving of repeated flexing.I've been doing some research and hope that hot bar soldering can overcome the assembly problems.But I do have this little problem of finding the stuff first.

author: Simon
author_rank: Unknown
timestamp: April 15, 2014, 11:38:31 am
content: how about a thin wire with silicone sleeving, the main cause of stiffness in wire is the insulation.

author: RoadRunner
author_rank: Frequent Contributor
timestamp: April 15, 2014, 11:49:32 am
content: Quote from: ehler on April 15, 2014, 11:36:52 ami used to do a little trick to solder these type of wire ,all you have to is first you tint the wire with fairly high temperature , it will burn the varnish like insulation on the copper wire , but copper will be there and solder will be tint every single wire. then low the the temperature and do the regular stuff.this works for me very well.

author: ehler
author_rank: Newbie
timestamp: April 15, 2014, 11:59:44 am
content: Simon:I think that sleeve material could be a help in my googling.Gaurav:I also found that a dab with a flux pen helped the tinning, the plastic reinforcer was still there but I think I got a good joint.

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 15, 2014, 12:06:39 pm
content: That is called "tinsel wire" and it is commonly used in applications that need very flexible cabling. Practically all quality headphones, for example, use tinsel wire. Note that, by itself, tinsel wire is very weak and will not last very long, unsupported. And, as others have mentioned already, while the insulation provides much of the mechanical support, it also tends to add stiffness as well.However, it is extraordinarily difficult to terminate. Many of us who repair and hack things try to solder to it. While this can be done, it is VERY fiddly and often takes several attempts to get it right without breaking the ultra-fine strands. In commercial applications, it is not unusual to find crimped connections.I would strongly suggest that you re-consider your decision to use short pieces of tinsel wire soldered to the boards. Unless you are making only a tiny quantity, I think you will find this a monumental pain in the neck. There are several options, and re-designing the project to NOT need such board-to-board compliance is something I would strongly consider.

author: Simon
author_rank: Unknown
timestamp: April 15, 2014, 12:10:37 pm
content: http://uk.farnell.com/alpha-wire/39x2205-wh005/wire-silicone-5kv-22awg-30-5m/dp/1843259

author: ehler
author_rank: Newbie
timestamp: April 15, 2014, 01:40:06 pm
content: Thanks Simon.and thank you Richard, 'Tinsel' is the magic word.I'm considering a few options. The main mechanical stress is being handled by a silicone moulding across the joint, forming the 'hinge'. What I need from my conductors are fitting down the 2mm canyon between boards, and a lifetime of flexing. I'm running the wires into the joint and along it, not straight across, I'm hoping this makes the wire take the mechanical shifting as a twist along the length not a bend with very short radii. A bit like a laptop hinge. I can't design the flex out of the system as the flex is the whole point.I have been trying to work out a geometry that would allow me to use flex pcb, but I think the radii and the repeated stresses would be too much for the foil. Which sent me looking for multi stranded cable.It would be great to know how headphone manufacturers terminate the stuff. Underpaid staff with an iron? Spot welding? Hot bar?Thank you all for your help, great forum.

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 15, 2014, 05:27:33 pm
content: Quote from: ehler on April 15, 2014, 01:40:06 pmAs I already mentioned, commercial use is frequently terminated with (very tiny) crimp-lugs.Tinsel wire is actually non-conductive fibre core ("string") with very thin ribbons of copper spiral-wrapped around the core. This was invented around 100 years ago by the telephone industry. If you dissemble old telephone gear, you will see tinsel wire and crimp lugs everywhere.Note, that if you don't simultaneously mechanically attach to the fibre core (by using a crimp lug) you are leaving that very tiny copper ribbon out there on its own, and it will quickly fail if it is flexed very much. That is why soldering is not used commercially.