What safety precautions can I use for an amplifier?

  1. I do alot of electronics and have built high power amps at home, im making one for my dad and I am putting the outputs on delayed relays so you do not hear the pop when the amp turns on and off, but I just remembered that there are other instances which will turn off the relay for safety,

    as I was typing this I realized I could have it turn off if for any reason the positive and negative supply were to come off or maybe a fuse blows causeing one to disconnect, but what other reasons could I add in for safety?

    I have surge protection taken care of but i had an old receiver fail once where it was putting out 36vdc and almost blew my woofers, i am trying to design some type of simple analog dc censor but do any of you know how I could do that or know of other things that may go wrong which I should add in?

    thanks
     
  2. jcsd
  3. mfb

    Staff: Mentor

    It would be helpful to know the application you have in mind.
     
  4. Bobbywhy

    Bobbywhy 1,908
    Gold Member

    Consider conditions that might occur:
    Over/Under voltage
    Over/Under current
    Over/Under? temperature
    Blown fuse
    Water intrusion?
    Cooling fan air flow failure

    These functions can easily be monitored and fed to a "Window Comparator" where you set the upper and lower limits. You may even insert time delays. Use Google to find examples, or data sheets from the manufacturers with application notes.
     
  5. thanks bobbywhy those are some good ideas.

    mfb,

    it is just 120watt subwoofer amp, i do not need information on anything but i've asked, I am very experienced in electronics. Do you have any other suggestions for precautions?
     
  6. You could sense proper amp biasing, verify no DC on the output amp, and verify no hip-hop is being played.
     
  7. Good one!
     
  8. There are really three things you want to protect:

    Protect speaker from failed amp.
    Protect amp from failed speaker (or more likely shorted wires).
    Protect human from failed amp.

    The third one is the most important, make sure you understand which appliance class is applicable (probably class I), hazardous voltage limits, and your insulation/creepage/clearance/earthing rules.
     
  9. Thats a great way to put it! I will be sure to follow those
     
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