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will this setup blow my amp??

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Old 11-13-2008, 02:10 PM
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will this setup blow my amp??

hello all,

can anyone tell me if i use a jl 300/4 amp to power 2 focal speakers up front and bridge 2 channels to a JL 12w3v2 sub.. will it blow the amp? I usually dont blast my music but like it loud enough.. someone told me that this setup is not enough power for my sub and that the amp will overheat.. just wanted to know if anyone has tried this before with this amp??

thanks!
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Old 11-13-2008, 06:20 PM
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No, it won't blow the amp. According to the spec sheet for this subwoofer the 150W you're feeding it is towards the minimum of its recommended RMS range.
The only issue I could see, is if you're turning the gains all the way up on the amplifier to try and force it to drive that sub more. If you're using what you have correctly, no you won't have a huge amount of bass, but you shouldn't be damaging anything either. You're just not using that subwoofer to its full potential.
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Old 11-13-2008, 07:03 PM
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yes you can damage your amp with this sub. It is within the power requirements as mentioned above. However that sub has dual voice coils and if you have the dual 2 configuration and it's hooked up in parrallel(1 ohm load) you CAN damage the amp. If you have the dual 2 config. you will have to hook the voice coils up in series.
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Old 11-13-2008, 07:27 PM
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i just took out the sub and at the back it does say its a D2, just curious.. if i do end up going with the jl 300/4 amp.. and its really not enough power then does it really matter if i go with a JL amp for sound quality? or can I just go with a cheaper alpine or phoenix gold amp that has more power.. and it will sound just as good or better.. i am really on a budget.. its just someone told me that i should go with a brandname amp like JL.. but dont really want to spend that much $$ any advice would be appreciated.
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Old 11-13-2008, 07:46 PM
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was just reading up on the JL 300/4 amp.. apparently if i use 2 ohm speakers on 2 channels (my sub) and then 4 ohm speakers on other 2 channels then, the 4 ohm speakers will only get 37.5 watt rms for the front speakers.. i guess this amp is no good for me.. do all amps work like this?
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Old 11-13-2008, 08:53 PM
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Why not just buy an appropriate amp for the sub and use a separate amp for your speakers? Or just buy a five channel amp? By not buying JL you could probably afford to do it.
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Old 11-13-2008, 11:24 PM
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i really want to avoid using 2 amps.. if i just want to power the fronts and a sub.. then i will have 2 channels not in use with a 5ch amp.. is the 5th channel usually made specifically for subs? i did see a phoenix gold 5ch amp for sale in the classifieds.. maybe that will do??
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Old 11-14-2008, 04:11 AM
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Your amp is too tiny for double duty.
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Old 11-14-2008, 07:22 AM
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Yes, the 5th channel is designed to power a subwoofer. I can understand your logic, seems like a waste of money if you're not using the rear channels.

I've done some quick snooping around...

According to the Focal website, chances are you are using 4 ohm speakers, which have an RMS of about 60-80W. That range seems to be constant throughout their speaker line up, unless you're using 4" speakers.

The JL sub has an RMS wattage of 300.

In my humble opinion, you should consider this amp.
Pioneer Premier PRS-D4200F <<< click the red text
It'll give you 75W x 2 @ 4ohm for your Focals. And 300W x 1 (bridged) @ 4 ohms for your subwoofer.
On the Pioneer site it states that their suggested retail price is $500USD. On Crutchfield, the JL 300/4 amp is $550USD.
I was already looking at the D4200F at a local shop in town. He'd let is go for $450CDN. He also suggested a Hertz HP4 4ch amp.
The Hertz amp puts out 130W x 2 @ 4 ohm, and 440W x 1 (bridged) @ 4 ohm. I have an email from this shop where they say the HP4 would be $400. I'm not sure if putting that much power to your Focals would be a cause for concern though. Someone else could shed some light of what doubling the RMS would do.

Hope that helps.
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Old 11-14-2008, 08:16 AM
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hmm.. ic not bad.. my sub is 2 ohm though.. doesnt that mean the power doubles or something?
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