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Thread: Amp selection

  1. #1
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    Amp selection

    Hey guys, i just fried my amp...errr. Anyways i believe it was a directed 800 watt, but thats beside the fact. I have 2 JL 12's (12W 1v2.4) and I need to know what type of amp i really need to get to replace my dead one. I may be wrong but i feel like my 800 watt amp wasnt powering the subs to their full potential. The way the sub were hooked up to the amp was the subs negatives were twisted together and ran to one of the negative connects on the amp and the positives were done the same way. On the amp it had enough negative and positives to hook them up individually( 2 pos, and 2 neg), so does that mean its a 2 channel? And the way they were hooked up being twist together does that mean they were bridged? Sorry about all the questions, i know im not that smart when it comes to the car audio topic. thanks

  2. #2
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    Before taking a look at your old amp specs, having two terminals does not always mean it is 2 channel. Some monoblock amps come with two terminals to make it easier for you to install two subwoofers, but internally the channels are bridged so it doesn't matter if you use one set or two, the load is the same.

    Now... when you put all the negative wires together and all the positive wires together, that means you're wiring in parallel (as opposed to series where the positive from one sub goes to the negative of the other sub and then the remaining pos and neg wires go to the amp to form a daisy chain). That kind of setup will halve the load, so two 4 ohm drivers will create an 8 ohm load, which reduces power output of the amplifier but can allow the amp to run cooler and sound relatively cleaner.

    The subs are rated at 300w each and have a resistance of 4 ohms each. So, the way you had them wired yielded a 2ohm load on the amplifier. This is typical of most monoblock subwoofer setups. Basically any 2ohm capable class D monoblock amp with 600w or so should work out for you.

    I'll suggest some if I think of any, but that should get the ball rolling. Price of course is a factor...

  3. #3
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    i see, ive got a concept amp that i was going to see if i could use, it came out of my dads chevy 2500 and he had it powering his door speakers and acouple smaller subs. Its a concept CC-554(ill post a link with some of it descriptions at the bottom). from what im gathering it has 480 Watts... but that of course wont be enough. I guess give me some suggestions if you dont mind with out me having to spend too much(meaning not the absolute best on the market).

    Oh yeah if this helps, i have a 2006 silverado with bose, so the set up i had was with the bose amp powering just the factory door speaker, and the amp the just died power just the 2 12's which were the bass.

  4. #4
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    That concept amp is a 5 channel amp from what I gather. The amp won't work for you. It is 200w bridged on the sub channel at 4 ohm. You need a 2 ohm amp. You could use it for one of the subs.

    I really don't know where to start with suggestions without an idea of how much you want to spend.

    Here's one for $320 JBL PX300.4

    Another JBL for $250 GTO601.1II

  5. #5
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    Quote Originally Posted by HyperZulu View Post
    Now... when you put all the negative wires together and all the positive wires together, that means you're wiring in parallel (as opposed to series where the positive from one sub goes to the negative of the other sub and then the remaining pos and neg wires go to the amp to form a daisy chain). That kind of setup will halve the load, so two 4 ohm drivers will create an 8 ohm load,
    I think this was just a typo, but I didn't want anyone to get confused:

    two 4 ohm drivers wired in parallel will make a 2 ohm load.
    two 4 ohm drivers wired in series will make a 8 ohm load.

  6. #6
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    Yeah I wasn't very clear there.

  7. #7
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    Ok, so the amp I had was a directed d800 mono. And if I was running it like you said the it was at 400X1 at 2 oh, does that mean that I had a total of 400 watts going to both subs or just one? And would it better to get a 600 watt amp or get one like I already had? Thanks

  8. #8
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    The amp you had is 300w x1 @ 2ohm. So each sub got a max of 150w.

    I really should stress though that when talking about driving a speaker to its full potential, we're talking about pushing a speaker near its mechanical limits, which is not necessary (or advisable). If your previous setup was not loud enough, you might consider a different enclosure, such as going ported if you can fit the box for it. Different enclosures are also different in their efficiency. A sealed enclosure is generally going to take more power to get as loud as a ported enclosure will off less power.

    Not trying to discourage anything at all. If you have 300w for each speaker, by all means use them, but most speakers won't see more than a couple decibels more output when doubling the power to them. For most, it's just headroom to play around with. You won't have to drive your amps as hard to get the same output from your speakers... But don't be dead set on a number. Just find something you are comfortable with and see if it'll work. I usually look for brands that worth what you pay for them and see if something in their lineup works for me.

    With all that said, a 600w x 1 @ 2ohm amp is what you want to give your subs what they can take. But you don't need exactly 600w. Reasonably more or less is fine.

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