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Subwoofer fuse - surge protection any good?

Discussion in 'Subwoofers' started by BenPremium, Jun 22, 2005.

  1. BenPremium

    BenPremium
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    My fuse has blown inside my sub.

    I noticed that whenever the bathroom shower light switch is pulled the sub makes a loud thud noise. Also when the switch is pulled my old amp used to cut out for 2 seconds. I'm guessing that the light switch is causing a power surge which is what used to trip the surge protection on the amp and blew the fuse in the sub.

    If I used a surge protector extension cable for the sub would this prevent the fuse blowing in the future?

    Thanks

    Ben
     
  2. bob1

    bob1
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    If the shower switch is causing the problem i would look into replacing that first.
     
  3. Reiner

    Reiner
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    Replace the switch. Maybe you can find one that has an electronic component (capacitor) inside which should prevent the spikes.
     
  4. BenPremium

    BenPremium
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    No way it'll happen unfortunately. It's my dad's house I'm in for the next couple of months and if it's not affecting him he won't change it :(

    Will a surge protector help do you think?
     
  5. bob1

    bob1
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    If the switch is causing the pops like you say the switch could well be faulty , even dirty contacts on a high ampage switch like a shower can cause the wiring and the switch to burn out, i would get him to at least look into it just for the sake of safety.A surge protector could help ,trying one is the only shure way to find out.
     
  6. BenPremium

    BenPremium
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    Thanks, I'll mention the safety aspects to him.
     
  7. u32t5645

    u32t5645
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    My thought is unless you are running that bathroom light in series behind your sub, the sub is in parallel with the light. There is nothing that light switch can do, however defective, to cause the sub to demand more current. It can only take current away from the sub with something like a ground fault.

    The fuse (a current limiting device) in the sub pops as a result of over current, too many amps at whatever voltage trying to get past the fuse. The current is pulled in behind the fuse, not pushed in from in front of it. For the sub to be popping a fuse the demand for the current must exist inside the sub.
     
  8. bob1

    bob1
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    Its the loud thud the sub is making thats causing the sub to blow fuses,thats an internal thing but the cause is external ,the arching in the shower switch.If the sub was at fault i would expect every switch in the house to cause some kind of pop on the sub.
    Reiner as the right idea suppression capacitors might be the only way to solve it.
     
  9. Reiner

    Reiner
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    I agree but the switch can cause a surge that is picked up by the sub's electronic circuit and then amplified, causing the thud.

    Using a surge protector may help but it only supresses the symptoms instead of addressing the cause (i.e. the switch).
     
  10. Nick_UK

    Nick_UK
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    I'm afraid you have a very naive view of electrical/electronics theory. If you put a switch in series with an inductive load, the collapsing magnetic field when you open the switch induces a high voltage to be created, and this produces a "spike" of higher voltage on the entire ring main. Although the element in a shower will present a load which is mainly resistive, the element will still be coiled, so there will be some inductive load present, and it's this (coupled with the high current flowing in the shower element) that causes the "splash" when the switch is operated.

    The fuse blows because (according to Ohm's Law) a higher voltage presented across a load will cause a higher current to flow. Although the high current only flows for a brief period, it's obviously enough for the fuse to blow. A surge limiter might do the trick, but it would have to be a pretty good one, not one of these £15 efforts from DIY stores.
     
  11. BenPremium

    BenPremium
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    Thanks for the replies.

    The strange thing is it didn't do it with my old sub which was the exact same model. The sub is a Servo-15 (I sold one before but now have one again) and this problem never used to occur. The spike is obviously the same as before because the shower switch causes the protection circuitry to come into effect in the amp but the old sub never used to pop.

    Now I get quite a loud thud every time the switch is pulled and the surge protection power cable that I'm using does nothing it seems.

    Is this damaging the sub? I'm moving into my uni house permanently in 3 weeks time so won't ever have the sub back home. Will 3 more weeks of popping (the fuse seems to be surviving now) do damage to the sub do you think?
     
  12. bob1

    bob1
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    Try having baths :D ,hose pipe ban imminent :( .
     

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