Weird headphone leads phenomenon?

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graham-xrf

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I have a Philips headphone set that can only be called "a bit old", They be the "comfy" kind with the padded earphone large enough to fit over the entire ear, so against the head, aviator style.

For the third time now, I am cutting off the wires, and re-connecting from lead further back. Fortunately the twin-lead is well long enough to keep supplying fresh lead replacement. It's always the same. The last 9" or so of wire leading up to the earphone "goes very stiff". So inflexible that the wire breaks inside the plastic right near the earphone. The thing is, it is always the LEFT side that suffers this. The right side remains fully flexible, as does the remainder of the lead.

Very, very strange!

My best speculation is that maybe the left side sees more light from the window, but it's a North facing window, so no direct sunlight, and I thought UV gets blocked by glass anyway. Deterioration from light in this way hardly seems likely. I tried a couple of bluetooth phones with audio adapters, but none could be the "comfy" kind, and the presence of the adapter took over to exclude all other audio channel controls. The other adapter type that goes in the audio line socket and "transmits" to the phones just hit distortion way too easily.

So - back to the solder iron and tweezers. Once more, I will make it work for a last fling before I finally dump them. :)
 
I have pair I bought overseas in 71'. They weigh a ton, but the sound is phenomenal. Don't use them that often, and they stay in a drawer, so still look like new. Koss brand I believe. Occasionally lay on the floor and listen to Lead Zeppelin, or Pink Floyd, to recapture my youth. Cheers, Mike
 
The left phone could be offgassing some evil chemical fumes that attacks the wire?
Or, that batch of wire is somehow defective? I've seen import plastic break down in myriad ways.
Have you seen what happens to plastic foam after many decades? It crumbles to dust
-M
 
When you reconnect the leads are you using Solder? If so, could it be a reaction to the flux or residual flux?
 
A form of "ear muffs" were supplied to engine room crews at least as far back as the '60s. A derivative of sound powered phone headsets, most likely, that go back to WW2 or better. In later years, once hard hats were required in the mills, the same ear muffs could be attached to the hard hat. At USSteel, headsets were used that were from the aviation industry for operators that sat at the machines. From all this usage, I have been sort of partial to the design, keeping a set of stereo headphones of the same form. My hearing leaves a lot to be desired, but is still fair enough to enjoy them. Both for music and computer based audio books. What with too long hair and a dirty environment, modern "ear buds" just don't do it for me.

The end result: I have a set (plus a couple more still in the box) of Koss headphones from Amazon. They were cheap, likely because they aren't popular these days.

Amazon.com: Koss UR20 Over-Ear Headphones, Flexible Sling Headband, Black: Stereophone: Home Audio & Theater

Amazon.com: Koss UR20 Over-Ear Headphones, Flexible Sling Headband, Black: Stereophone: Home Audio & Theater
www.amazon.com
There are several designs, this one is the one I have. Stereo, although I have the computer sound set to monoaural. The only problem I have had with them is that I am very big, 6ft3in, with body parts in proportion and long (messy) hair. The adjustable headband is stretched to the maximum to fit. They have broken in the clasp, but ACC (super glue) holds them fine.

Further, as an electronicist, I have a small spool of the shielded stereo cabling to repair them as necessary. The tiny little plug is a bit hard to handle at my age, I make up the ends with 1/4 phono plugs and use adapters. If things work out in the future, I will acquire a couple more extension cables and cut the female end away to make cords. The repairs are simple enough, with the phone cables being a pair of tiny co-ax cables, the only issue is to match the center conductor polarity. With my hearing marginalized over the years by heavy machinery, I'm not too particular about phasing speakers, but it is a consideration.

The concern expressed by the OP about the wire jacket is a charactistic of old plastic jacketed cable. I can't explain why one side hardens before the other. My philosophy is "it happens, deal with it". I would suggest acquiring an extension cable with the appropriate connector and replacing the existing cable. With excess length as appropriate. In the steel mill, where the operators sat next to the mold full of molten steel, plastic jacketed cable had a very short lifespan. We, in the electronics shop, attributed the failure rate to heat. Summer time as a mold operator is only one or two steps from Hell, even with portable fresh air machines.(winter wasn't much better) We dealt with it by acquiring 1000 ft spools of cable and using large plugs. And recabling headphones on a constant basis. Since earphones had personal contact, each operator had his own set. I'm sure coiling and handling had some effect on the cable as well.

.
 
If the jacket is going brittle, I don't have a cause for you. But if the wire is breaking, it is most likely work hardening. Electrical wire starts life in a fully annealed form. Every time it flexes, it work hardens a little. The point of contact has the highest stress and is where the break occurs. Strain reliefs help. Headphones from years gone by, as well as microphone and telephone handsets, used a very fine conductor wound around a fiber string to reduce this stress. Miserable to solder though.
 
DAT510 said:
When you reconnect the leads are you using Solder? If so, could it be a reaction to the flux or residual flux?
Click to expand...
Yes - I use solder. The leads are well designed audio construction. That means the signal, and return are each highly spun, tiny, like fine coil wire, and as a twisted pair with the return, also high rate of twist. Both together are still a tiny 0.5mm rope in the centre of a 2mm flexible plastic. Then, the two leads come together to make a pair - like thicker version lamp lead, but built for Hi-Fi.

Audio cables have to be like this. The wires must not take the strain, and they must not ruck up under the insulation cover. Soldering on the last 2mm of a lead cannot affect how the plastic of the lead gets to go stiff over about 200mm.

The cut leads are still on my desk. The right side one is floppy flexible. The left side one could be used to stir a sundowner (er.. that's a tall fruity cocktail in Africa and Australia) !
 
RJSakowski said:
If the jacket is going brittle, I don't have a cause for you. But if the wire is breaking, it is most likely work hardening. Electrical wire starts life in a fully annealed form. Every time it flexes, it work hardens a little. The point of contact has the highest stress and is where the break occurs. Strain reliefs help. Headphones from years gone by, as well as microphone and telephone handsets, used a very fine conductor wound around a fiber string to reduce this stress. Miserable to solder though.
Click to expand...

It's the jacket. Once the jacket is stiff, then it causes high stress bends right at the point it enters the earphone body, as it swings about.
I discover that glass stops nearly all UVB, but that 75% of UVA goes right through. Also, I find that those transparent little plastic sort trays do deteriorate in that light (screw tray sorter left on window sill).

I know the plastics in that speculation are different, but now I think that if the plastic has polyvinyl with chlorine in it, then sunlight could well make a difference. I recall from school that almost all reactions involving chlorine seemed to rev up some when shown some sunlight, and some lab bottles were brown, to stop that happening.

Duh - darn, but the silliest things get me curious.
 
@Bi11Hudson :
Thanks for the link. I know the type.
My favourite has to be the AeroCom comfies with the final cotton edge elasticated over covers that can be washed or replaced. These are as fitted to the common airplane communication headsets. Maybe not actually Hi-Fi, but very comfy. I once had the (yuk) job of going through the fleet (7 aircraft), and "maintaining" these. The leads had a central strain cord, yellow string stuff, that was pretty much unbreakable, and the jacks were quality 1/4" TRS, internally arranged so the strain string was secured shorter than the wires.

Pilot's crappy muffled audio fault along with mad noise was usually down to the double-sided noise cancelling microphone having it's little holes clogged up with bits of old sandwich, whatever, on the face side. I finally got fed up with it, so I spoke to the boss who decreed that pilots take their headsets away in their flight bags, and not just swap the faulty ones for better headsets to be found in another plane.

BTW - those style headsets are still unreasonably expensive!"
 
To confirm your suspicions, cut the flexible lead in half and lay both halves on the window sill, one covered.
 
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