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XLR Doesn't Work...?

Discussion in 'Recording' started by JohnCellar, Jan 13, 2013.

  1. JohnCellar

    JohnCellar Active Member

    Okay, so one of my mic cables hasn't worked for a while. I simply don't get a signal from it.

    Usually when this happens, I pop open the connectors and find a short in it, or one of the connections tore off or something. Then I can just solder the thing back together, and bingo.. problem solved. But here's the thing, the cable appears to be perfectly fine. No bad connections, nothing. I've treated the thing great; it's always been indoors, I've coiled it up properly, I've literally looked the entire thing over and haven't found a thing.

    So what else could be the problem? It the thing just trash now? It's the weirdest thing. Has anybody else had this problem before? Any ideas for further troubleshooting? It's frustrating because it's such a simple thing. Three wires... it seems any problem would be blatantly obvious.
     
  2. thatjeffguy

    thatjeffguy Active Member

    A simple continuity test can narrow down your problem. If you don't have a dedicated cable tester, use a simple inexpensive volt-ohm meter to check the end-to-end continuity of each conductor. This will at least narrow it down to which of the conductors is faulty. Then focus on the connection of each end of that particular conductor. Faulty solder joints can often appear to be perfectly good but still not be conducting. If nothing else try re-soldering these connections.
    Hope this helps.
    Jeff
     
  3. Kapt.Krunch

    Kapt.Krunch Well-Known Member

    The first question anyone should ask, given the info provided, is "Have you tried another cable with the exact same equipment, to be more certain it's the cable"?

    Not to insinuate that you didn't think of that. You probably did. It just wasn't stated, even though it might be deduced, somewhat, from your first sentence, being as you said "ONE of my cables", etc.

    Just making sure the picture is more clear for further analysis.

    Kapt.Krunch
     
  4. JohnCellar

    JohnCellar Active Member

    Okay... cool. I think I'm just going to re-solder each connection, because it'll take a few minutes. I just figured if it was still attached, it was a good solder.

    And yes, I have used other equipment. I should have said that. This particular XLR has been broken for almost a year now, and I've been using the same mics, mixers, interfaces, etc. with other cables without fail.
     
  5. thatjeffguy

    thatjeffguy Active Member

    From Wikipedia:

    Various problems may arise in the soldering process which lead to joints which are nonfunctional either immediately or after a period of use.
    The most common defect when hand-soldering results from the parts being joined not exceeding the solder's liquidus temperature, resulting in a "cold solder" joint. This is usually the result of the soldering iron being used to heat the solder directly, rather than the parts themselves. Properly done, the iron heats the parts to be connected, which in turn melt the solder, guaranteeing adequate heat in the joined parts for thorough wetting. In electronic hand soldering the flux is embedded in the solder. Therefore heating the solder first may cause the flux to evaporate before it cleans the surfaces being soldered. A cold-soldered joint may not conduct at all, or may conduct only intermittently. Cold-soldered joints also happen in mass production, and are a common cause of equipment which passes testing, but malfunctions after sometimes years of operation. A "dry joint" occurs when the cooling solder is moved, and often occurs because the joint moves when the soldering iron is removed from the joint.

    Just FYI
    Jeff
     
  6. Boswell

    Boswell Moderator Distinguished Member

    The probable explanation is that there is an unintended contact between the two inner conductors somewhere in the cable or its XLR connectors. This would be the equivalent of using a microphone fitted with an on-off switch and turning it to "off".

    As suggested, an ohm-meter would give you the real picture. If it does show a short between pins 2 and 3 on the XLRs, it may be a matter of using a magnifying glass to inspect the insides of the connectors. If that shows nothing, go along the cable length carefully feeling for lumps or other irregularities that may indicate internal damage.

    A few years ago, I bought a reel of medium-quality microphone cable to wire up fixed links in a studio. Two of the 16 links did not work, meter measurements showing there were open circuits in one of the conductors in both links. After much effort, I found that the conductors had been joined within the cable during manufacture, and the joints had ruptured even with minimal flexing. I didn't buy from that supplier again.
     
  7. audiokid

    audiokid Staff

    Wow, interesting Boswell!

    I want to invest in a good meter. What do you recommend for the standard studio?
     
  8. dvdhawk

    dvdhawk Well-Known Member

    In addition to the obvious (pinched in a case lid, pinched under a chair leg, having your snake driven over by the bass player's drunk Uncle Joe) - something as simple as a shoe/boot with a hard heel is all it takes to damage a mic cable internally. And just about anybody who deals in large quantities of cable has received a cable, or spool of wire with a break or short somewhere in the middle. If you think about the manufacturing process, it's a wonder they can make reliable multi-strand, multi-pair cables as well as they do.


    I'm also interested in what Boswell would suggest, but until he checks back in, here are a few US/Canadian based recommendations from someone far less qualified...


    This is an Audio Cable Tester I recommend to my customers. It's easy to use and reliably tests a wide variety of cables. The LEDs can indicated if there's a short, a reversed pair, or just plain no continuity pin by pin. [ This one tests 1/4" TRS/TS, XLR, RCA, SpeakOn, MIDI, DMX, Banana plugs & Cat5 ] There are pared down versions too. It's considerably easier than holding two cables ends and wrangling two probes - keeping track of the which pin is which.

    For the times you really need a AC or DC voltage reading / ohm measurement etc. you need a meter with probes rather than a simple cable tester box. If I were recommending a reasonably priced DMM I'd look at something like this Velleman Digital Multimeter.

    Companies like Velleman, Klein, and even RadioShack sell a decent affordable meter that would be more than adequate for virtually anything you'd ever want to do.

    If you want something more accurate / more upscale Triplett, Fluke, B&K, Amprobe are all excellent and commercial grade.

    A case could be made for having an analog VOM meter too. You don't get the same easy-to-read accuracy of a digital readout, but analog meters can react much faster to voltages that fluctuate.
     
  9. audiokid

    audiokid Staff

    Thanks Dave.
     
  10. Boswell

    Boswell Moderator Distinguished Member

    I would think that Hawk's suggestions are good. The lower-end DMMs that I know tend to be European-branded ones, and, while each may be identical to one available in N America, it's probably under a different brand name.

    The DMM unit I use the most is an Iso-Tech IDM 305 - not the cheapest, but very good. As well as most common ranges, it has true r.m.s. readings and a dB scale down to around -90dBu. They are probably now superceded, but were available at the time with a calibration certificate for a bit more money.
     
  11. dvdhawk

    dvdhawk Well-Known Member

    RadioShack, or The Source I guess it would be in Canada, should have a reasonably priced model that will do the job. A digital meter like this, for example. You'll notice in the description, "auto power-off", that's very handy in a digital meter if you're shopping elsewhere. If left unused for a few minutes it will power-down to conserve the battery.

    Some of the vendors I deal with sell cheap basic digital multimeters starting at $5 - $10, and occasionally I will buy a couple when they're on sale to leave at installations so they can accurately test batteries (for wireless mics) and do simple continuity tests. What the vendors of these $5 meters fail to tell you is that once the battery is dead you might as well toss the whole meter in the trash. For some reason, some meters use odd (in other words, hard to find / expensive) batteries, and if you forget to turn it off once it's done for. The cost of replacing the battery is just idiotic and you learn your lesson. Obviously, one should have reasonable expectations of a $5 meter.

    That would not be an issue with an analog version, which would typically use no power if you forget to turn it off.
     
  12. audiokid

    audiokid Staff

    Dave, thanks for posting these links to the store here.
     
  13. rmburrow

    rmburrow Active Member

    John: Have you encountered a XLR mic cable connector where one of the pins was hairline broken INSIDE the insert? Sometimes this will show on a ohmmeter test, but the intermittent nature of a hairline break suggests the connector should simply be replaced. This happens more on male XLR connectors that are often connected and disconnected from equipment.
     

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