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Discussion Starter · #1 ·
Hello, I have acquired myself a Rockford fosgate subwoofer out of a junkyard eclipse. The woofer is rated 75 watt at 1ohm and is a dual voice coil.

I ended up finding an alpine amp with close to the same ratings and is very small for a nice stealth build. The amp is rated 90 watt at 1ohm or 60 watt at 2ohm

My question is how would you go about wiring a sub with dual voice could to this amp pics attached for an idea.

Thanks for the help!
 

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Discussion Starter · #3 ·
Thanks, I am assuming based on the specs of my amp I want to run in series due to possible damage at 0.5 ohm
 

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Correct
 

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No problem, enjoy.
 

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Just learned something that I always just asked a friend about.
 

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I ended up finding an alpine amp with close to the same ratings and is very small for a nice stealth build. The amp is rated 90 watt at 1ohm or 60 watt at 2ohm
is the amp you are using the KTP-190U?

because if so, the power rating is not really that close at all... since the alpine is not half ohm stable, you will have to run the subs coils in series, so it will be 2 ohm which will have a power output of 60 watts.

that sub is rated 75w per coil... so its a 150w sub, and that amp will only be sending it a little over a 1/3 of what it needs.




also, if that is the amp you are going to use, its really tricky to get it right, I just got done last week putting one of those into a SLK that got a new radio and had the Harmon Kardon amp bypassed and needed something to power and keep the front door subs working. the biggest issue I have with it is that it is only high level in (not that big of a deal using a factory radio) but it also does not have any gain setting, so there is no way of getting the amps input level matched up and correct... there is an input to use one of alpines remote bass knobs which could be used to cut the level of output down (but with as under powered that setup will be, I dont think that will be of much use)
 

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Discussion Starter · #9 ·
is the amp you are using the KTP-190U?

because if so, the power rating is not really that close at all... since the alpine is not half ohm stable, you will have to run the subs coils in series, so it will be 2 ohm which will have a power output of 60 watts.

that sub is rated 75w per coil... so its a 150w sub, and that amp will only be sending it a little over a 1/3 of what it needs.




also, if that is the amp you are going to use, its really tricky to get it right, I just got done last week putting one of those into a SLK that got a new radio and had the Harmon Kardon amp bypassed and needed something to power and keep the front door subs working. the biggest issue I have with it is that it is only high level in (not that big of a deal using a factory radio) but it also does not have any gain setting, so there is no way of getting the amps input level matched up and correct... there is an input to use one of alpines remote bass knobs which could be used to cut the level of output down (but with as under powered that setup will be, I dont think that will be of much use)
I see I misunderstood the ratings on the subwoofer itself, yes it was the ktp-190u I have it all wired and working now and of course I is quiet. I suspected it would be, but now I want to try to drive the sub better knowing it can handle more than I thought.
 

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well you could always buy a second mono power pack amp and run one per coil , then each amp will be driven to full power @ 1ohm per coil/amp. since there is no gain adjustment, you really dont have to be concerned about getting the levels matched up right between both amps. only down side is that is going to be at or maybe slightly over the subs limit and there is not really much that you can back it down a hair.
 
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