little wiring help, if you have time :)

Discussion in 'OT Technology' started by Jesse_Boyer, Feb 7, 2006.

  1. Jesse_Boyer

    Jesse_Boyer New Member

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    I'm trying to wire my 800a2 to my new aluminum eclipse 10"; model SW8102. this is a DVC sub, btw.

    amp info:
    RMS Power at 4 Ohms 200 W x 2
    RMS Power at 2 Ohms 400 W x 2
    Bridged power 800 x 1 @ 4 ohms (I think)

    the amp is bridged now, but I can certainly change it to whatever you like.

    Right now, I have both voice coils hooked to each respective terminal. both positives to the positive on the amp... both neg's to the neg on the amp.

    It's drawing a TON of current right now. much more than the last sub I ran. I'm thinking about removing one of voice coils and running the amp bridged to one VC. It sounds great at volume, but it sure does draw a ton of current.

    help if you can...
     
  2. funkbucket007

    funkbucket007 New Member

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    What impedance are the voice coils on that sub?
     
  3. Jesse_Boyer

    Jesse_Boyer New Member

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    4 ohm per coil



    I've got it wired for 2-ohm now, but i'm not sure if the 800a2 is stable at 2-ohm. Plus, it's rated for 800 x 1 @ 4 ohm (benched at 1017W) and I'm certain I'm going to tare the alt out at this level. Wouldn't it theoretically be doing 2 x 800 x 1? meaning 1600W? that's just crazy talk considering I only run one battery, no cap (working on it) and one single aluminum 10"...

    Jesse is confused, apparently
     
  4. eighteen_psi

    eighteen_psi Active Member

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    First...do NOT drive one coil without the other...and do NOT drive them with different signals (signal on one and none on the other is quite different)...unless you detest the sub and wish to break it :(

    Wiring those coils in parallel will produce a 2 ohm load...which is where you want things IF the amp is stable into 2 ohm mono. If it's not, you don't have the ideal sub for that amp. You'd either need a pair of them, or a single, dual 2 ohm sub (to wire in series to create a single 4 ohm load).

    And...

    The power is produced into the load of the entire circuit so the output is divided among things on the circuit. 800W at 2 ohm could be 800W into a single 2 ohm sub...or 400 each into a pair of 4 ohm subs in parallel...etc.

    This is just physics...every time you halve impedance (ohms) you double the power output. This works only in theory..in practice your amp will go into protection, overheat or simply blow up if you were to, say, hook up a 1/4 ohm load to it. But there are amps that are stable into such a load..and they continue to double their power every halving.

    Note: Regulating an amp can also slow this process...which is why some make less than double each halving.

    Also, pretty much everyone benches amps under ideal conditions that aren't seen in most (if any) daily driven cars...sustaining 1kW of output on a class AB amp requires somewhere in the neighborhood of 140 amps at 12V...which I can safely assume it's not getting.

    That's not to say it won't be plenty loud...cause it ought to be :big grin:

    If you want to reduce output, either go super conservative on the gain (assuming the amp is 2 ohm mono stable), or wire in series..this will seriously reduce the output and current draw.

    For an amp that size to get proper power, you need at least GOOD 4 gauge power...perhaps 2 (assuming no other amps). You also need an alternator in the neighborhood of 180 amps, if not more (depending on what your vehicle needs to function properly). All grounds and charge cables everywhere need to be of the same gauge as the feed for the amp too. A 1F cap can help but don't expect it to do much without the rest. A cap smooths out transient loads for quick peaks but it can't make power from nowhere. Another battery does nothing but increase the time you can knock it before the car won't start :)

    All the above assumes you want it up full all the time...obviously you don't need that much alternator if you wire it down or go easy on the gains. But if you don't, and do get hard on it, you're gonna starve it for power and clip..and likely ruin your sub. So don't :)

    That help? Confuse you more?
     
    Last edited: Feb 7, 2006
  5. Jesse_Boyer

    Jesse_Boyer New Member

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    it all helps, but i'm still not sure what I'm going to do...

    I'm going to try 8-ohm tonight and see how quiet it gets. Hopefully, that'll still be loud enough to satisfy me and my alt/charging system.

    If not, i'll throw my buddies 1.5 farad cap on, take the gain down, and run it. The shop I bought the sub from said my 800a2 would be stable at 2-ohm, but I'm not sure. The guys on the other forum said I shouldn't try it.

    For what it's worth, I've got Monster 4-ga power cable, 2-ga ground (I think), only running the one amp, stock GM alt. on my '99 C5.

    Definitely not getting 140amps constant, that's certain.
     
  6. pharcyde183

    pharcyde183 Nissan by nature

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    8ohm will be fine. that sub is 500RMS 8ohm if it benched 1000+ at 4 you will get 500 or so @8 so you'll be giving it RMS
     
  7. Jesse_Boyer

    Jesse_Boyer New Member

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    I rewired the sub so the amp see's an 8-ohm load and it's plenty loud . Plus, since the amp is drawing much less current, the I don't think I need a capacitor. We're good to go for a while now...
     
  8. FyreDaug

    FyreDaug lolswift

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    Yeah you just cut the power into 1/4. That should be plenty loud still
     

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