Making audio cables is one of those things that I do without really thinking… I’ve made cables for so many years that it’s become second nature. It’s drop-dead easy as well… every audio person should make their own cables unless you’re just plain swamped with jobs. Not only will your finished cables be less expensive, but with care they’ll be higher quality than most of the cables that you’ll buy. All you need are a few tools, some QUALITY components, some time, and a place to work. (Exception- Hirose connectors or mini XLR types (TA-3, TA4, or Lectro mic input TA-5 types) are NOT easy to solder. I’ve done it, so it is possible, but you certainly don’t want to try these if you’re just starting out. I use a stereo dissection microscope when working with these kinds of connectors.)
- A soldering iron (NOT a soldering gun). I have a Weller 25w and a 35w. The 35w has a little extra heat and power to melt solder on larger, heavier terminals, but I generally prefer my 25w with a fine conical tip. Smaller connectors, such as 3.5mm stereo jacks or the tiny Hirose require an iron with the finest tip you can get. Avoid cheap soldering irons… they are slow to heat and can damage semiconductors.
- Wire strippers. These range from simple and cheap (4-5 bucks) to automatic wire strippers (about 25 bucks). I always went the cheapskate route, until I finally bought a good, US-made pair of automatic strippers about a year ago. I should’ve bought these from the get-go… they work very well, and are much faster and easier than the cheap methods. For the truly frugal, you can use an Xacto knife, but be careful not to nick the conductors. Some wires are too fine for the auto strippers, so a knife isn’t a bad idea anyway.
- Wire cutters. I have several sizes and styles. My favorites, though, are my Xuron flush-cutters, for small wires only. (Again, these are US-made… are we starting to see a pattern here?) Large shielded cables require standard-size wire cutters.
- A heat source. A candle can work, but I finally bought a proper heat gun for shrinking heat-shrink tubing. Smoke from the candle sometimes leaves soot marks on your cables, which looks dirty.
- DVM or analog voltage meter for checking the circuits. An analog meter works fine, but the digital units are generally more capable. A cheap Chinese meter can be bought from Harbor Freight on sale for under five dollars these days, and will work for checking solder joints or batteries. If you spend some money for a good meter, though, these can measure all kinds of things, like inductance, capacitance, temperature, frequency. Try to get one with an auto shutoff feature. A real Fluke meter is on my wish list.
- Other tools are sometimes required, but not essential for every job. I have an assortment of tweezers, including the locking type for soldering- handy, especially for smaller connectors. I also have a rack of jeweler’s pliers that I reach for often.
- Quality audio cable. This is NOT the area to hunt for bargains. I use only cable by Canare or Mogami. Belden is an old standard. Good cable is expensive for a reason. It is completely pointless to do all this work if you can’t trust the cable itself, so get the real deal.
- Connectors. I prefer Neutrik over the old Switchcraft types, but both are quality products. Neutrik cables have a different strain relief design and can be disassembled in the field without tools, which is important for troubleshooting connection problems. The newer Switchcraft connectors have been redesigned and may make the differences less pronounced. But definitely stay away from anything selling direct from overseas on eBay.
- Solder. I purchased a large spool of fine rosin-core solder when my 20-year old spool from Radio Shack finally started looking thin. 60/40 solder containing lead is getting difficult to find, so buy some while you can. The flux is the key, buy solder from a reputable electronics supplier and you’ll be fine. But AVOID lead-free solder until you’re an expert… it may be better for the environment, but it’s much more difficult to solder than 60/40.
- Heatshrink tubing. Here’s the detail that will make your cables last longer than most ready-made cables. Adding a length or two of heatshrink takes a few minutes, but it distributes the strain of the cable better and protects the soldered joints. The cable shouldn’t move when you hold the connector still- add heatshrink until the cable matches the size of the hole in the connector shell. You can even take the extra step and add another layer of heatshrink outside of the connector shell, but this makes repairs more difficult. Another heatshrink trick is to buy a length of clear tubing. Label your cables with your name, then cover the label with a piece of clear for a permanent ID. Don’t use electrical tape on your connectors… it never lasts very long, and leaves a sticky residue when you remove it in order to do the job properly. Sometimes heatshrink is impossible to fit and you may have to use it to insulate something, but when I do I always finish it with a layer of heat shrink.
Actually building your cables is fairly simple. First, cut the cable to length. Because I have forgotten to do it SO many times, my next step is always to insert the screw-on connector shells. I’ll put on both ends facing back-to-back. Even though you don’t need to do this until after you’ve soldered your first cable end, I promise you that someday, somewhere, you’ll forget to add a shell and will have to cut off and re-solder a connector. Hopefully no one will be around to witness your dumb mistake, but I would challenge anyone who has built more than five cables who says they’ve NEVER forgotten a shell.
Add your label and clear heatshrink to ID the cable as yours. Strip the ends, leaving the leads fairly short, around a half inch. This ensures that the little plastic clutch will squeeze the outer shield, making your cable durable. (I’m assuming Neutrik connectors, Switchcraft may be different.) If you leave the leads too long, the plastic clutch will be totally ineffective, your soldered joints will stress from movement, and your cable will fail in a fairly short time. Build up the area that the clutch grabs with a length of heatshrink, about two inches should do it.
Now strip the individual leads and twist the strands. It sometimes makes life a little easier if you heat and tin the bare ends with a tiny spot of solder before you attempt to solder the connector, this prevents flyaway strands that could potentially cause a short. Not absolutely essential, though, if you’re careful, but it does make things easier later.
Pin 1 is the cable shield. Always. No exceptions. Well, maybe one…except when you’re wiring a “Starquad” or four-conductor cable, see below. If you are using standard audio cable with two conductors and a shield, then pin 1 is always connected to the shield. Pin two and three are for the signal positive and signal negative. This won’t matter when building the cable as long as the same wire goes to the same pin on each end. If you aren’t careful and solder pin 2 on one end to pin 3 on the other, then you’ve built a phase-reversing cable. If you use this cable alone with a single mic, no problem. But you’ll hear some weird effects if a mis-wired cable is used in a stereo pair.
Should you tie the connector shells?
On your connector you will notice a fourth lug. This is to provide an electrical connection to the outside of the shell of the connector. You will often see commercially-made cables made with this lug soldered to pin 1. This way, the shield of the audio cable is electrically connected to the metal case of the gear, which is grounded through the power outlet to the real earth somewhere. Hopefully. The trouble starts when you have a piece of gear that’s faulty, and some of the power supply voltage is being drained off by the case. Or… and this has happened to me once… you have a power outlet that’s incorrectly wired, and the ground at one outlet is a different potential from the ground of another… and both outlets are used in your signal chain. (I learned this the very hard way. saw a 1/4″ spark jump tp pin 1 when I went to plug in my audio cable… “What the FUç&?!…” while several people stood by me wondering when their $20,000 satellite shot was going to have sound.) There is a host of possible scenarios regarding grounding of audio equipment, and the best explanation I’ve found is by Rane called Grounding and Shielding Audio Devices. It tells you more than you wanted to know about grounding. But even more essential to the cable builder is Rane’s Note 110, Sound system interconnection. Read this before you build any cables… it covers all sorts of different cable types and ends, and tells you exactly how you should wire, say, a cable with a female XLR on one end and an unbalanced RCA at the other.
There is one cable type that isn’t mentioned in Rane 110, and that’s “Starquad” or “Neglex” cables. These cable types have four conductors surrounded by a shield, rather than the usual two, though only three conductors are used for balanced cables. To wire a Starquad cable, pins 1, 2, and 3 are connected to an inner conductor. The shield is connected to the cable shell at the male end only, with the shield and extra conductor cut short at the female end.
The advantage of this type of cable is the audio ground is kept separate from the chassis ground. The chassis ground is used to surround the audio conductors, protecting them from EMI (Electro Magnetic Interference). I’ve built a few of these and they work well.