Fortunately, I don't work for the bomb squad.

May 12, 2009 9:19 PM

I need to do some wire splicing on a set of desktop speakers and I'd like some suggestions for improvement.

Hey Ask, thanks in advance. I have a run-of-the-mill 2.1 Logitech computer speaker set-up. A quarter-inch jack lead to a wired remote, which leads to a subwoofer, which connects to two smaller speakers. The male 1/4 inch jack that would ordinarily connect to the line out of my laptop's sound card has suffered some wear and/or corrosion. Consequently, rotating the jack allows me to hear audio out of at most one external speaker at a time. Attempts to clean the jack with pencil erasers and rubbing alcohol (separately) have revealed that the problem is at least partly damageds surfaces and failed to remedy it. The internal line-out connection (female) on the sound card is working fine as tested with two sets of headphones.

Here's my plan to fix the jack problem:
1. Buy any cheap device or cable with a 1/4 inch male jack, preferably at a flexible right angle to the cable. Buy a small roll of electrical tape.
2. Cut off the existing jack and remove the molding (but not the inner layer of insulation) around about an inch of the cable that used to connect the jack and the wired remote.
3. Remove the insulation from a small section of the wire and prepare the new cable in a like manner: leave the jack at one end connected to a ~6" piece of the cable it was attached to with the other end stripped.
4. Connect the two stripped sections by twisting, and cover up just past the stripped section of each old cable with tightly wrapped electrical tape.

If I happen to find a wire cap small enough to accomodate the two wires, I'll use that in addition to the electrical tape.

How can I improve on this procedure? Am I doing anything stupid? Any blindingly obvious improvements I'm missing?

Thanks.

posted by Inspector.Gadget to technology (10 comments total)

You can try sanding the corrosion off to make a better contact.
posted by wongcorgi at 9:34 PM on May 12

You can buy a replacement plug at your local Radio Shack store. You'll want to solder the connections to avoid them pulling apart & ensure a solid electrical connection.
posted by torquemaniac at 9:39 PM on May 12

In my opinion this is not going to work well enough to bother. I think you'd be better off bying a 1/8th plug itself, cutting the cord, stripping the cable and soldering to the plug. I just doubt you'll get a good consistent connection by twisting and using electrical tape.

Depending on the device, you might be better off opening it up and desoldering the whole line from the device and soldering on a whole new line, either salvaged from another device or make one yourself out of sturdier cable and plug. If you make your own you'll have the benefit of easily being able to repair it.

Commercial cables for these computer speakers, headphones, etc, tend to use pretty small gauge wires that are really hard to work with, imo, and also the insulation isn't really meant to be easily strippable, it can be pretty hard to deal with, without tearing the strands of the wire.
posted by RustyBrooks at 9:43 PM on May 12

Also it's possible that the wear/corrosion is in the audio out of your computer, not in the speaker plug? Might want to try a 2nd set of speakers first.
posted by RustyBrooks at 9:44 PM on May 12

Depending on the cable, you may have an outer layer of wire underneath the insulation, with another insulation layer under it and then the inner wire. The outer layer of wire, if it is there, is indeed a conductor. I'd say go with Rusty Brooks' suggestion of just re-running the wire.
posted by azpenguin at 12:09 AM on May 13

It should have high enough quality to achieve your goals, including longevity.

That said, in order for it to do that, it needs to have reliable connections, mechanically and electrically sound. They should be covered up against chemical and mechanical damage. "Pretty" may/may not be one of your criteria and that's your choice.

My way of splicing cables that I can't replace uses soldered connections, shrink wrap of appropriate diameter for each splice, and a larger piece of shrink wrap for the entire bundle of the spliced area.

Rustybrooks is correct... these things are tiny and hard to manipulate. Even getting a good strip is hard. Also, cables are pretty cheap, and if you are not uncomfortable INSIDE the speakers, you might want to avoid the splice on the outside and just remove/replace the cable where it attaches internally. About the same level of aggravation. You may also want to put a removable connector hack in place so that you can change the cable out in the future in the event of another failure. Radio Shack sells RCA phono jacks and other connectors you might be able to retrofit.
posted by FauxScot at 12:48 AM on May 13

use a telephone wire splice kit. very easy to use, no stripping the wire involved. and it works every time. this is the solution.
posted by Flood at 4:25 AM on May 13

Don't try to get fancy here. Twisting them together and wrapping them in tape will work just fine. I wouldn't bother with solder or shrink wrap here, it's really not necessary. I'd skip the wire caps as well, as they will just add bulk.

I have spliced countless cords and cables this way over the years, and they always function well enough to get me by.
posted by davey_darling at 4:55 AM on May 13

I'd go for the quick and dirty splicing method first and see how well that works. If it quickly becomes a mess (some of those thin cables aren't exactly user serviceable), I'd pick up a generic pre-made cable with a 1/4" connector (think you may mean 1/8", but whatever your laptop has), cut the other end off, open up the remote, and solder the bare wires directly into the remote. This way, your only attachment point is inside the remote, which ought to be easier to work with.

I'll also add the general tip should you choose to go with torquemaniac's approach that 1/4" connectors are much easier to solder than 1/8" connectors. Solder the 1/4" connector and use a cheapie adapter.

You could also try some contact cleaner on the jack first. If it just needs cleaning off, this will save you a fair bit of trouble.
posted by zachlipton at 5:32 AM on May 13

I'd go for the quick and dirty splicing method first and see how well that works

It may not work at all. Often, these cables are varnish-coating to insulate the conductors from each other.

Telco Splices will work if the conductors are the right size, and they won't work if they're not. As with most things telco, they're built to not need stripping (which takes time and often damages the conductor) or soldering (which takes time, and is often done poorly, thus resulting in a bad circuit.) Don't over crimp them -- the right answer is to get the tool used to crimp them, but you can do them with pliers, as long as you are careful.

Tape splicing is almost never adequate. For larger conductors, the right answer is to splice with wire nuts, for smaller, telco splices.
posted by eriko at 8:43 AM on May 13