Harmony Central Forums
Announcement Announcement Module
No announcement yet.

Mic Cables With Noticeable Volume Differences

Page Title Module
Move Remove Collapse

Conversation Detail Module
  • Filter
  • Time
  • Show
Clear All
new posts

  • Mic Cables With Noticeable Volume Differences

    A while back, I ordered four of this type of cable.  I got them from an eBay seller, used but in like new condition.  I hadn't used them before last weekend.

    Rapco Switched Microphone Cable

    I had to turn the gain up on every channel I had them on (all vocals). They all needed about the same adjustment.  I never really thought much about possible differences in resistance or whatever might cause this.  Is this common with the switched cables or with certain brands of cables? 

    EDIT:  There was no difference in the quality of sound or clarity of the mics.

    Attached Files

  • #2

    Only a problem on improperly made cables, or those that have defects. Something is definately wrong with them.


    • gruven65
      gruven65 commented
      Editing a comment

      But would the defect be the same across all four cables? Seems odd. Is there a way to improperly wire the cables that would cause a perceived volume loss?


    • WynnD
      WynnD commented
      Editing a comment
      My bet is that they all have the signal ground jumped to the shield too. That would result in about a 6 db drop and a potential increase in noise. There is some possibility that this won't occur with every mixer, but will occur with better mixers. (MixWiz and better.)

  • #3

    gruven65 wrote:

    EDIT:  There was no difference in the quality of sound or clarity of the mics.

    Maybe not on a superficial listen, but the fact is that you're cranking the preamp gains to compensate. That brings in more noise and THD. You are not getting the cleanest, strongest possible signal from the source that you should be getting.

    Say, it seems to say Neutrik, at least on the male connector. Is the switched one also Neutrik? If so, I'd expect better, oops. Maybe it's counterfeit, or some of their made-in-China stuff.

    Sounds like there is some nasty parastic resistance in there which is significant with respect to the input impedance of the console and the source impedance of the mic. I.e more than a few ohms.

    Check the DC resistance of each of the cable's three conductors with a digital multimeter. Ideally, it should be close to zero, like a fraction of an ohm.

    Also, are these cables substantially longer than cables that you're used to? What cable are you comparing it to, and what are the specs for both? Are there any markings on the cable, like indication of the wire gauge? Is there a brand name and model number printed on the cable itself (not the connectors)?

    It could be that the connectors are fine, but the cable is very resistive. That would also be consistent between different cables of the same length (whereas a flaky on-off switch would likely vary between units).

    Music DIY mailing list: http://www.kylheku.com/diy
    ADA MP-1 mailing list: http://www.kylheku.com/mp1


    • gruven65
      gruven65 commented
      Editing a comment

      I never said I had to "crank" the gains.  The preamps were still below 50% of their possible adjustment.  I just noticed what I consider a big adjustment (like from 9:30 to 110).

      I'll check the resistance as soon as I'm able.  I have a multimeter, but I had only checked continuity with a cable tester. 

      The cables are 25 feet long. The other cables were possibly 20 feet, but I'm not sure.  5 feet +- shouldn't be a significant difference though.

  • #4
    Good to know.


    • wesg
      wesg commented
      Editing a comment
      Hee hee. It's always important to check from first principles. I have to admit, magically moving knobs would not have crossed my mind.

      I used to be a computer tech in another life, the first thing I would ask customers to do in a no-start situation was to verify that it was plugged in. You'd be surprised how often they weren't.