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christopher vournazos

chris@chrisvo.co
765.238.9061

Make the right connection

Wiring, as much as if not more than any other factor, makes or breaks not just one project but your whole studio. But what your wiring is made of is not as important as how it's terminated, and that can mean the difference between smooth sailing and migraines.
2014-03-30
Engineering

Sorry, oxygen-free copper folks, this just ain't your day.

Now, to be clear, I am not going to suggest that you take the crappiest old wire you have and run unbalanced audio a couple hundred feet across your house and around all your spiffy CFL bulbs.

What I am saying is that you can do dirty wiring things you would never admit to your neighbors, indulge cabling fetishes that you must never, ever reveal to even your closest friends, and still get fine results. Results that are, in fact, indistinguishable from those achieved with the most expensive cabling.

Good cabling equals clean signal, no unwanted noise, happy clients, fields of pretty flowers. Bad cabling equals unreliable signal, noise, hum, and lots of lost time tracing wires and figuring out which one is the culprit. But "good cabling" does not have to equal "expensive cabling."

I assert that the proper connector, attached securely and properly to the end of your cable, is more important than what the cabling itself is made of. Where plain ol' audio is concerned, this is just a fact. Let's agree at this point that even the most expensive cable is completely worthless if the connector on either end is broken, is loose because it's not attached securely, or is simply attached incorrectly.

Try your own blind test with whatever conductors you have at hand, and read this article by cabling expert Steve Lampen about just such a test with a whole auditorium full of audio engineers as victims here .

Before you go any further, pull down the blinds. You may even want to clear your cache and read this page in an incognito window. What follows may seem, to the closed-minded, outright heresy.

Your studio and mine are probably a lot alike: you have roughly five million cables going to places you can no longer find and aren't even sure you knew where were in the first place. Where you and I may differ is that you purchase every cable you need, and I make my own. There is nothing wrong with either approach, but my way saves a ton of cash. The DIY approach also means you can make cables of precisely the length needed and take advantage of materials you may already have just laying around.

As an added bonus, you'll probably wind up learning cool stuff along the way and picking up some nifty new engineering skills, too.

No, I'm not suggesting you go grab your jumper cables or some barbed wire. So close the trunk of your car, and let's just begin with a look at your balanced audio cabling - e.g., for microphone and line-level thingies that are probably the main thingies you've got going on.

What I'm getting at here is this: since nearly all of the analog audio signals in your studio should be balanced, what you use for wiring simply doesn't matter as much as you've been led to believe. Build your cables carefully and correctly, and you won't ever again need to spend $50 on a microphone cable with XLR connectors. It's a fun way to thumb your nose at the audiophiles.

Where I do admit to being finicky...

The connector itself - I've settled on Neutrik for XLRs. No, I do not believe they somehow conduct the signal better or differently than the ones you used to get from RadioShack (R.I.P, *sniff*). I prefer the Neutrik connectors because they're more rugged, and they've got that cool strain relief sleeve. The whole connector just feels solid, and you can order them in massive quantities for very little cost.

Precious Metals

Another thing to keep in mind: gold-plated connectors generally mean absolutely nothing to your audio quality or even the longevity of your wiring. If your recording environment is really so prone to corrosion that it's an issue, you're probably better off moving your whole studio elsewhere. For almost all of us, plain old copper is fine - and silver is, too: another fun little secret is that silver is a superior conductor to both copper and gold. But it's not nearly as exciting, I suppose, to brag to your friends about your silver connectors.

Unless you plan to brag about your connectors to werewolves.

Then it might just save your life, because they'll be afraid and stay away.

Snap, Crackle, POP!

What can cause big trouble for any kind of conductor is a dirty plug or a dirty jack. Over time, crud (that's a scientific term) can build up on your connectors. XLRs aren't so susceptible, but 1/4" plugs and jacks certainly are. Crud build-up can keep the contacts in the jack from getting very intimate with the conductive part of the plug.

Bits of crud can also act like a bunch of tiny antennae, slurping up all the stray RF that floats by.

Grab a 1/4" plug and twist it a bit in the jack - hear the snap-crackle-pops? You need to clean your connectors. Pick up some contact cleaner spray at your local supply place. Just remember to disconnect from power before you hose down your connectors, and then dry everything thoroughly before you power it back up. Compressed air will help get things dry quicker.

Isopropyl alcohol can also be used instead of contact cleaner, but be sure it's more alcohol than not. The average drugstore rubbing alcohol usually has too much water content, and you don't wanna wipe water all in your jacks...

Nifty Tip

A cleaning swab is useful in cleaning jacks. Don't use a regular cotton swab, though - they leave little strands of cotton behind, which is equivalent to the crud you're trying to remove. The foam-headed swabs are good in this case.

If you must use regular cotton swabs, you'll need to blow out or vacuum out the jack when you're done. Vacuuming may be better than blowing, since you might get the jack clean, but blow all the swab-droppings (and other crud) all over the circuit board or other components.

And you don't want that.

What's a prime bringer of crud?

Oil from your skin, dirt from your hands. Wash those hands, my friend. Not messing with your plugs all the time helps, too - less you touch them, less dirty they get. And don't smoke over your equipment. Now that I'm officially a non-smoker, I can ride you about that all I want.

If Cleaning Doesn't Seem To Help...

Take a good look at your plugs. You may need a magnifying glass to see any scratches, pits, rust or other nasties that have taken up residence. If it's not something that's easily removed by a good cleaning, hack off the plug and reterminate. Connectors are cheap, but reliability and your time are priceless.

"Colors Have Their Harmony..." - Professor Von Drake

Pick and stick is the guiding principle: pick a color scheme, then stick to it. A documented wire color scheme is critical when another engineer comes along after you to work on wiring you installed. But it's still a serious timesaver even when nobody but you will ever even see your wiring, because you can glance at a wire and instantly know what is (or is supposed to be) flowing through it. It also keeps your forehead from hurting, since sticking to a color scheme keeps your hand from needing to slap it so much.

Well, sometimes color does matter...

Certain cabling generally adheres to standardized color schemes. USB cabling is a good example of this, as is your household electrical wiring. In the former case, not sticking to the scheme probably means you'll ruin a device when you plug it in; in the latter, you could be killed, or worse.

Putting aside twist differences in different kinds of multiwire cabling, and assuming you don't have some weird cable where the wires are each of vastly different gauges, what color you choose to carry which part of the signal in your audio wiring doesn't really matter. There really are only two rules:

  1. Document your color choices.
  2. Keep the documentation where you can find and refer to it.

So document, document, document. Everything that's written down and accessible is everything you don't have to try to remember, only to remember that you already forgot.

Pinout Pinup

Color scheme and how nice your connectors are don't mean squat if the wires are connected to the wrong pins. Depending on what you're connecting, all the pins, most of the pins, or just a couple of the pins may actually be used. In every case you must, without fail, make sure the right pins on one end have continuity to the right pins on the other end.

With most kinds of audio signal connectors, it's pretty straightforward, because the wires go directly from each pin on one end of the cable to the same pin on the other end. Other cabling doesn't always work that way. A perfect example is the good ol' serial cable with the DB9 connector. For most serial applications, you need transmit, receive and ground, which are pins 3, 2 and 5, respectively. While pin 5 on one end goes to pin 5 on the other, most of the time you'll actually need pin 3 on one end to go to pin 2 on the other. The name for this is "null modem," but what it simply means is that you've directed one end's mouth to the other end's ear.

If you did not cross pins 2 and 3, you would wind up connecting one end's mouth to the other end's mouth. Not only is that kinda salacious of you, but it results in both ends talking and nobody listening.

The rule here is that, while there are often no rules on color choices, you absolutely must follow the rules on how the wires actually get connected to the connector. If you don't make sure of that, nothing else will matter, because it simply won't work.

Let the internet be your exocortex, and just look up the pinout you need when you need it. A no-frills site for this purpose is pinouts.ru, where you'll find most kinds of connectors for nearly any purpose.

If you want to be really cool and impress your friends, get the ElectroDroid app for your phone - electrodroid.it. It features not only pinouts for nearly everything, but calculators, electronic component lookup tables, circuit simulation, and all manner of stuff, if you would like to go a little further in your schooling.

The Fine Print

Depending on what you want to do, what you need to do, and how much time you want to spend doing it, building your own cables can be fun and save you money. You also get bragging rights because you made something.

If you're in a big hurry, are no good with your hands, are afraid of a soldering iron or simply aren't at all interested in tinkering, then you can still stick with buying cables. No shame will come to you, either way.

Finally, this is not intended to be official advice for any purpose - it's anecdotal, at best, and if you hurt yourself or blow something up because you've done anything I've said, sorry for your luck. Also, my suggestions - in my experience - prove workable over short distances. Please keep that in mind.

But since this is all so much fun, for those who want to continue our little engineering primer, look for the next entry in this series, when we'll go over some of the basic tools you should have at your disposal. Nothing expensive, and all readily available online or at your favorite electronics supply store.

By the way...

Before we get to the next installment, the folks at Rane have some really good material in their library. This article on grounding and shielding audio devices is originally from 1995, but has aged well and is still accurate. It's worth your time to read it: Rane Note #151

Sounds like a good time!