Subwoofer Pop (Boom)

Discussion in 'Home Theater Projects' started by Anthony_I, Oct 17, 2004.

  1. Anthony_I

    Anthony_I Stunt Coordinator

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    I will try and make this simple to understand but i have a custom modified sub amp from rythmik audio. im not using it currently added relay circuit yet but i do have a 12V power supply tapped off of the incoming 120V power on the amp (where the plug goes inside to the back of the amp i have a 120VAC -> 12VDC transformer tapped off of it)
    the tap is added before the amps PSU, so it is not putting any drain on the amps psu.

    HOWEVER i have a switch wired in that allows me to cut the 120VAC power to the 12V transformer...turning it off and keeping heat out.

    when i turn the switch on or off it usually makes a huge pop or bang noise (no bottoming out though) which im guessing is from the switch arcing.

    how can i solve this.... i found this on another site... is it accurate and will it work? or is there any other circuit i can build?

     
  2. Wayne A. Pflughaupt

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    Your post is a bit confusing, Anthony. Are you talking about the power switch on the amp, or a separate one that you have wired in across the main 120 VAC service? Also, I don’t get what the 12V transformer has to do with anything. If it’s plugged into an outlet the back of the amp (which is the way I read it) it shouldn’t be an issue for a turn-on pop.

    Regards,
    Wayne A. Pflughaupt
     
  3. Anthony_I

    Anthony_I Stunt Coordinator

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    ummm...sorry, your right it is confusing.
    it is another switch that is wired into the 120V service....but this is tapped off the amps incoming 120V power before the amps power supply.

    Now this power tap, as it were, provides power to a 12V transformer (step down ... 120VAC -> 12VDC)
    This power supply runs various lights (i built a party sub)
    but when i flip the switch to cut the 120V power to the step down transformer, it makes my sub pop... loudly....and only sometimes, it happens randomly.

    i hope i cleared it up
    it is 7am and im just getting off of work... so when i wake up i will try and draw a diagram of what im talking about.
     
  4. Wayne A. Pflughaupt

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    You mean internally? As in, inside the amp’s chassis?

    I’m not sure what a lighted party sub is all about, but since you switch them independently from the sub it looks like there’s no reason to power them like this – i.e., in a way that interferes with the sub.

    That aside, it would take someone with more knowledge of electronics than I have to tell you if the info from that other site is what you need. Since it comes from someone who did it and it worked, I suppose it would do the trick - if arcing is what is causing your problem. If it’s not arcing, then I imagine you need to find away to better isolate the lighting power from the amp’s

    That wiring diagram would be helpful, ‘cause I’m still not perfectly clear on what’s going on with your set-up. You can e-mail it to me, if that would be easier.

    Regards,
    Wayne A. Pflughaupt
     
  5. Anthony_I

    Anthony_I Stunt Coordinator

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    yes i mean internally.... it is all inside my box.

    Here is an extremely simple diagram that physically shows how it is all connected.

    it shows the amp from the back (Inside the box) and how i tapped the power.

    I realize that what ive built must seem retarded to a home theater crew, but it works for me [​IMG]

    http://kb.unrealt.com/attachment.php?attachmentid=881
     
  6. Wayne A. Pflughaupt

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    The diagram isn't coming up, Anthony.
     
  7. Anthony_I

    Anthony_I Stunt Coordinator

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    sorry im not sure why it isnt......but if there is somewhere to upload it i can fix it... cause i tried hotlinking it.
     
  8. Wayne A. Pflughaupt

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    Can you put it in a Word document and e-mail it to me?
     
  9. Anthony_I

    Anthony_I Stunt Coordinator

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    yeah that i can do... it is an extrmely simple diagram too i might add :)
     
  10. Wayne A. Pflughaupt

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    Thanks for sending the diagram, Anthony.

    For the record, the first post is an accurate description of how the transformer is hooked up.

    I really can’t see any good reason why the transformer is tapped off the amp’s incoming A/C. Maybe to switch it automatically when the amp comes on? But that’s pretty much negated by having a separate switch for the transformer.

    Thus I can’t see any good reason not to simply power the transformer directly from a wall outlet. Barring that, you could simply switch the lights from the 12v side.

    If neither of those scenarios work for you, then try the circuits recommend in the links you found. As noted, if the problem is cause by arcing, that may solve it.

    If that doesn’t do it, I suppose your only options are the ones I recommended - power the transformer directly from the wall, switch the 12v side - or live with it.

    Regards,
    Wayne A. Pflughaupt
     
  11. Anthony_I

    Anthony_I Stunt Coordinator

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    now heres the interesting thing about your suggestions.

    As you can see by the way it is tapped, it is essitanlly the same as powering it directly from the wall. only using 1 cord instead of 2 seperate ones.
    it is switched manually on the 120V side, as you can also see in the diagram, but im waiting on a part to finish a circuit which will switch the 12V side on or off with the amp. this was a custom mod already put on my amp when i ordered it [​IMG]

    so this already does both of what you suggested....
    all this is built inside of my sub box, thats why the 12V transformer is tapped from the amp that way, to keep it all inside the box.
     

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