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<Groan> cables again

Discussion in 'audio' started by CDphobe, Jan 12, 2021.

  1. CDphobe

    CDphobe pfm Member

    It seems there's a cable thread running smoothly and without the usual "discussions" so I thought it about time to open another thread to allow the more usual exchange of views <g>

    With the ongoing lockdown situation I'm having to re-think how I set a room up. I had been planning to knock through a wall to gain access to an understairs area that could have housed the main rack, but this would need an RSJ and so I'm giving up on that being possible for months yet. As an alternative I can relocate the main rack, retain just the power amps under the stairs and route speaker cables through the wall. However, that means a long interconnect run between sources and power amp, probably about 10-12m routed above the ceiling. Equipment is true balanced, so I've the benefit of some noise rejection, but its still a longer run than I've previously used - but then for pro-audio mic cables, lengths of 20m+ seem to be commonplace.

    So questions - should I even be bothered that it's a 10m+ interconnect? Are there any "limits" I should consider (capacitance, inductance)? Any additional considerations for the cable design?

    I'm not going to be able to swap this cable out, so it needs to be right first time. Do I buy a specialist hifi cable, any old mic cable that's long enough, or DIY it with a decent OCC cable, Raybraid and sleeve?

    Thoughts please

    Al
     
  2. Woodface

    Woodface pfm Member

    Sounds like a daft idea but it should work as balanced cables can do long runs.
     
    leroyd likes this.
  3. misterdog

    misterdog Not the canine kind

    CDphobe, AndyU and Zombie like this.
  4. stevec67

    stevec67 pfm Member

    Go for it, a long interconnect will work.
     
  5. david ellwood

    david ellwood Kirabosi Kognoscente

    Mogami neglex star quad is what I’d use.
     
    CDphobe and Salamander like this.
  6. Curtis

    Curtis pfm Member

    Personally I would use a professional audio cable manufacturer like van damme or klotz.
     
  7. misterdog

    misterdog Not the canine kind

    The Mogami cable with spiral shield is quicker to terminate than the Van Damme, though the Van Damme quad core has less Capacitance.

    Mogami Neglex 2534

    Cond.-Cond. 97pF/m
    Cond.-Shield.110pF/m

    Van Damme.
    Balanced quad core


    Core to core 48pF/m
    Core to screen 91pF/m

    The Van Damme costs from 0.43 p /M
    The Mogami costs from 0.78 p /M

    (Designacable prices for full reels presumably)

    Surely cable costing so little cannot be good enough for high quality domestic audio..

    Though it is good enough for the BBC and Abbey Road studios. ;)
     
    CDphobe, Millennium and Curtis like this.
  8. Curtis

    Curtis pfm Member

    Yup lol.
    It will leave you wondering what you are missing for the rest of your days!
    Lmao!
     
  9. misterdog

    misterdog Not the canine kind

    Only suitable for long runs or noisy environments though. Apparently.

    Though no-one has ever specified how long a long run is, longer than a Metre ?
    Or how noisy a hi-fi rack full of mains cables and Wi-Fi is.
     
    YNWOAN likes this.
  10. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Long runs will be fine and as ALWAYS any old cable will do fine.
     
    Martyn Miles, ampedup and chartz like this.
  11. stevec67

    stevec67 pfm Member

    It absolutely can't. It needs further processing to release its full potential. What you need to do is send it to me and I will cryogenically treat it, followed by a physical crystal realignment process, for £20 a linear metre of interconnect cable. Minimum order quantity £50, post free. PM will be fine. Speaker cable treatment also available, POA.
     
    naimplayer, CDphobe and misterdog like this.
  12. misterdog

    misterdog Not the canine kind

     
  13. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I never watch videos. Like I said, any old cable will be fine.
     
  14. Craig B

    Craig B Re:trophile

    Spoiler alert! Bloke demonstrates that one shouldn't lay power adapters, computer AC power cords, or devices with either switched mode or linear power supplies upon one's signal interconnects. However, if one is of the sort to be doing this anyway, then one should get one's self some star-quad cable.:)

    @CDphobe Al,

    Should you decide to go with star quad, and your sources and amp are RCA sockets, then this diagram shows the preferred RCA plug termination method for best noise rejection. Don't confuse the 'directional' bit with foo audiophile nonsense; In this case, direction refers to the cable shield being connected at the source end only, such that it doesn't act as signal conductor, but rather as shield only (i.e. by not being common to signal -ve at both ends).

    Credit: World's Best Cables:
    [​IMG]
     
    nobeone and CDphobe like this.
  15. stevec67

    stevec67 pfm Member

    175 hours burn-in time? If I do 2 hours, 3x pw, that's over 6 months!
     
  16. Darth Vader

    Darth Vader From the Dark Side

    Thats so by the time you have finished you'd have forgotten what it sounded like when new and wouldn't realise that it made no difference whatsoever.

    Cheers,

    DV
     
  17. Craig B

    Craig B Re:trophile

    Ah, yes, my apologies for not vetting the presentation slides better. Carry on.
     
  18. Jim Audiomisc

    Jim Audiomisc pfm Member

    The detail I didn't see was the output impedance of the signal source driving the cable runs. Probably fine, but that and the load at the other end tend to be something I'm aware of when using a long run. Home audio generally isn't impedance matched. However one of the systems I use has a couple of very long interconnect runs, so as per the above advice, you're probably OK.
     
    CDphobe and Arkless Electronics like this.
  19. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Yep that's one of the things that does matter but is never discussed... Too technical and no foo:rolleyes:
     
    Last edited by a moderator: Jan 14, 2021
    CDphobe likes this.
  20. CDphobe

    CDphobe pfm Member

    All,

    Thanks for all the inputs, I love this place :)

    To answer the techie bit first, its 100R into 47k so my limited knowledge suggests this should be fine?

    Craig, thanks for the diagram on use of StarQuad into phono, but I'm XLR throughout. On which basis, if I decide to DIY this, am I better to add a separate Raybraid screen on top of the "normal" cable types to allow screen as well as signal ground, or just not bother? The run I have identified crosses one 240V line (at right angles) and is otherwise 24" clear of power and aerials so can't see noise being a problem to be honest, and I'm more tempted to speak to a good, non-foo manufacturer like Blue Jeans Cable.

    Oh, and Stevec67? At only £20/m I'm tempted, I mean it can't do any harm right? But then, it sounds a bit cheap to do anything useful so I'll pass

    Al
     

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