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question about ohms and wiring for subs

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Old 01-26-2006, 10:29 AM
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Default question about ohms and wiring for subs

i currently have 2 12" 200w 4ohm subs running on a planet audio 300 watt anp. i got this amp for free and is is a http://cgi.ebay.com/CADENCE-Q3000-2-...QQcmdZViewItem
can i run this on my set up instead and how would i go about doing it ? thanx
Old 01-26-2006, 11:02 AM
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Well are your subs a dual voice coils?

If they are single voice coil and are wired in parallel dropping the load to 2 Ohms which from what that amps ratings it would be pushing 1 channel (both subs) at 600 peak watts. You would need to adjust your gain because the subs that you are referencing cumulatively can only handle 400W's. This method would give you MAXIMUM power, but you would need to be careful not to over drive them.

Another way you could run them is to just run each sub off of each channel which would run them at 50% and you would not run the risk of overpowering them.

Just some ideas, and here are a reference site for you to look at on your own as well.

http://www.the12volt.com/caraudio/boxcalcs.asp
Old 01-26-2006, 01:57 PM
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Thanx For The Info. What Would I Get If I Just Wired Them Separetly Like Pos To Sub Pos Neg To Sub Neg And The Ame Way For The Other Sub ?
Old 01-26-2006, 10:27 PM
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The problem is the amp is only 4 Ohm Stable Bridged. With those speakers, if you parallel them, this will overdrive the amp. The only option is running each of them in stereo mode.
Old 01-27-2006, 06:10 PM
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sorry to be dumb but what do you mean by overdrive the amp is that harmful to the subs of the amp ?
Old 01-27-2006, 06:50 PM
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Watching this thread. Ive always wanted to learn about this tuff.
Old 01-27-2006, 10:25 PM
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The amp does not appear to be stable at 2 Ohm in bridged mode. This can damage the amp and is not recommended. It would be best to have an amp that is stable at 2 ohm bridged.
Old 01-28-2006, 01:38 AM
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If you get a amp thats stable at 1 ohm is that fine to use for long periods of time?
Old 01-28-2006, 01:58 AM
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thats how i run mine....1 ohm, lately its been acting weird where i would have to wiggle the fuse in the distribution block for it to come on. but its been running strong for about a year now leading up to this problem.
Old 01-28-2006, 04:53 AM
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Originally Posted by Blacker
The problem is the amp is only 4 Ohm Stable Bridged. With those speakers, if you parallel them, this will overdrive the amp. The only option is running each of them in stereo mode.

He means that the ohms, the measure of resistance in terms of electrons, will be much less if you parallel the two subs and then bridge the amp. This may cause the amp to go into short circuit protection. It will indefiantly cause more heat to be created by the transistors in the amp and in turn shorten the life of your amplifier. Heat is the #1 cause of electronic failure. It would be best to get another amp just like the new one and put one sub per amp (bridged).
Old 01-28-2006, 10:04 AM
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so is there a different set of subs that i can buy to make this amp work and what would i have to look for ?
Old 01-28-2006, 02:37 PM
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You can either look for 2 dual voice coil 4 ohm subs or you can try to find 2 single voice coil 2 ohm subs.
Old 01-28-2006, 05:45 PM
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so a 2ohm svc os the answer thanx. whats the min wattage ? 300 ?
Old 01-30-2006, 10:36 AM
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Originally Posted by spy2520
thats how i run mine....1 ohm, lately its been acting weird where i would have to wiggle the fuse in the distribution block for it to come on. but its been running strong for about a year now leading up to this problem.

Spy
If you're still watching this thread, sounds like you have a cold solder joint where the fuse contatcs go into the PCB (green silicon board for most amps but it's the boadr all the componts asre soldered to). That or somewhere whit power coming in (power wire ground or somewhere in there) that when you wiggle the fuse it moves enough to make contact again. Running any amp 1 Ohm gets real hot (heck most amps get real warm/hot to the touch just running normal the 2 or 4 ohm set ups) This hot cold hot cold (on off on off) can and does cause the solder joints to crack as they expand and contract over time.
If this happens enough times the sudden "jolt" or spike of the power getting applied as well as the sparking caused by the cold solder joint can cause other componets to fail prematurely. a "soft on" (amp doen't cut on as soon as power is applied but a few seconds after to prevent noise being sent out through the system) amp won't have as much as a problem with it but still something to look at.




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