› Forums › Music › Sound Engineering › Thin balanced audio cable?

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  • November 14, 2012 at 10:03 pm #1054367
    General Lighting
    Moderator

      The original engineers at ICR-FM used this thin but good quality balanced audio cable (as thin as 2 pair CW1308 or a USB cable). This makes sense as there is a lot of cable in a radio studio, but it is usually a fixed install and left alone once there and needs to fit into thin spaces. Also this cable can be punched down to block terminal 237A (Krone block) in the control room.

      I am not sure what it is, anyone got any ideas? Though I will be there tomorrow evening if any other sound techs on here know it would be much appreciated, as some lads from a local band want to do a live set on the radio so I need to get the audio feed from their desk into the studio…

      November 14, 2012 at 10:22 pm #1262392
      cheeseweasel
      Participant

        VDC install cable?

        Or if you want even thinner there’s the console cable on that site, which is good for wiring jackfields and other fiddly jobs.

        November 14, 2012 at 10:40 pm #1262389
        General Lighting
        Moderator

          cheers mate thats the stuff, I think they were using the console cable. There might be some of it still in the pile of stuff moved from the other place. We got a bunch of stuff recovered from a “this is heart” type station where the local bit closed down as its all done from Norwich and jackfields etc are already wired onto these (the rest of the kit should be in my other thread about the station ) making things a lot easier.

          8168089900_7cc644f2c1_b_d.jpg.

          November 14, 2012 at 10:55 pm #1262393
          cheeseweasel
          Participant

            If you don’t find any and you’re after a cheaper solution (Van-Damme cable isn’t cheap), standard cat5 works well for balanced audio (it is twisted-pair after all, and IIRC has better common-mode rejection properties than audio-grade twisted pair as the twists are tighter/more frequent, though don’t quote me on that).

            Installations in stock exchanges commonly make use of the building’s network infrastructure to send balanced audio between trading floors etc as it works perfectly well* and removes the need for separate audio tie-lines running around the place. A pair of RJ45 plug > MXLR/FXLR adaptors might be a useful thing to make if you find the need to occasionally send audio to/from different parts of the building.

            * so long as no-one unwittingly sends +48v to the network racks! (Hmm… that gives me an idea for the next time I do a job in an investment bank… bye-bye billions…)

            November 16, 2012 at 1:45 am #1262390
            General Lighting
            Moderator

              cheers – did wonder about this although half the structured cabling is kaputt anyway (ironic as it was an electric/datacomms contractor before)), , we have barely enough working points to keep the computers going (and there are some dinosaurs there as well!). I think the VDC cable we did get was the remainder of a drum originally owned by a larger broadcaster whose studios downsized. Most of the studio is kept running by bits scrounged from other workplaces TBH (I donated them a somewhat temperamental Laserjet 6 that was from my old office and had ended up hanging around in my house for months, it still just about works and is the only printer they have at the moment!)

              @cheeseweasel 506334 wrote:

              * so long as no-one unwittingly sends +48v to the network racks! (Hmm… that gives me an idea for the next time I do a job in an investment bank… bye-bye billions…)

              -48V gets sent down structured cabling all the time on the inner pair (blue white/white blue) along with normal bog standard analogue telephone signals (which are also essentially balanced audio but two way) and if confined to these conductors it should do no harm even if inadvertantly plugged into a network switch or similar..

              November 16, 2012 at 1:50 am #1262394
              cheeseweasel
              Participant

                Ah fair enough. Shows the extent of my IT knowledge! What purpose does the -48V serve, out of interest?

                November 16, 2012 at 2:15 am #1262391
                General Lighting
                Moderator

                  Originally it provided the current to activate carbon microphones in the telephone, today it powers the circuitry to make the DTMF sender work, various audio amplifiers and buffers (which take the place of the hybrid transformer) and the presence or absence of the loop current flowing in the line is used for signalling (to ascertain if the telephone is picked up). There is also about 80-100V AC at 25Hz sent down a telephone to make it ring (originally for the bells, and was generated by turning a handle at the other end like in old movies.) this is unpleasant if you encounter it by touch…

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                › Forums › Music › Sound Engineering › Thin balanced audio cable?