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Can I Shield Alesis Monitor Ones?

Discussion in 'Monitoring / Headphones' started by ericeholtz, Mar 6, 2011.

  1. ericeholtz

    ericeholtz Active Member

    I have vintage Alesis Monitor One near-fields, which are unshielded. One of them has to sit right next to my vintage Zenith System 3 monitor--the layout cannot be altered. The monitor affects parts of the screen, depending on its angle, leading to my questions:
    1) Will the monitor proximity cause damage to the screen, even if the TV is off?
    2) Can I put something in between the monitor and the TV to provide shielding and if so, what would it be? Any comments and ideas would be greatly appreciated,
  2. Big K

    Big K Well-Known Member

    Hello Eric

    Welcome to our RO forum!

    Yes, it can harm the mask of the picture tube permanently, even when the TV is off.
    I looked up this here in 15 seconds:
    Shielding / Screening, Magneticfield shielding, RF & E-Field Shielding, electronic device Screening, Screening panels, Shielding foil, Shielding fabric, etc.     

    A few more inches between monitor and speakers would do the same trick, though.
  3. Link555

    Link555 Well-Known Member

    mu metal is the best magnetic shield i have used.
    About MuShield high permeability magnetic shielding material
  4. Big K

    Big K Well-Known Member

    If you use permalloy or Mu Metal, keep in mind that you must try not to deform it too much or to hammer it.
    The material looses its permeability quite dramatically, like μr=50.000 and when mechanically stressed only μr=150 is left.
  5. Boswell

    Boswell Moderator Distinguished Member

    Mumetal is undoubtedly the best material for this, but is both expensive and probably over the top for what you need. I would try a couple of sheets of plated mild steel ("tinplate") and experiment with those postioned between the monitor and the display. Test the suitability of the sheet by checking that a magnet will stick to it. Note that any alloy-based material is of no use for magnetic field screening.

    Most CRT displays have either auto-degauss on power on or a degauss option in their function controls, so you are unlikely to cause permanent disruption to the monitor operation.
  6. Big K

    Big K Well-Known Member

    Build-in Degaussing safes you only to a certain degree. I advice not to rely on this automated de-magnetising.
    I have fixed a bunch of picture tubes with an hand-held degausser because the damage through permanent magnetic fields
    had bend the mask beyond of what the build-in coil could fix. Most of those defects were caused by speakers.

    Something like here for 30 bucks might work for you ( with some search you'll find it cheaper)
  7. hueseph

    hueseph Well-Known Member

    Pardon me if I'm stepping out of line here but a Zenith System 3? Is that monitor really that good? A 15" LCD can be had for $100 that has as good if not better picture quality of a comparible CRT. I don't know. Am I missing something? I just tend to associate CRT monitors with problems in general. Noise being the most prominent one. I'm not claiming anything here. If I'm way off the path, please educate me. I've proven myself stupid many times before.

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