runner800
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Posts posted by runner800
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My alternator is rated at 145 amps according to Cadillac.
2088 watts to work with so you probably could get 1000 watts especially if you wire to 2ohms the amp is significantly more efficient at that "resting" load
So, to run the T2500 reliably, I'll need a Mechman Alt and an XS D3100. Since the time I posted this a few days ago I have all but decided that a new Alt and battery will be purchased shortly after acquiring the amp.
That sounds like plenty the t2500 is lovely if I wasn't so poor...
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yeah my guess is your ohms rise was closer to 2 ohms. i never seen a fosgate do less then rated even on poor electrical(at a short burp period) also how long did you burp it?
I did the measurement as an after thought for a physics final project last year, the actual goal was to measure the efficiency of the amp, I had probably been running a tone for about 8 to 10 min total that day. The amp can do the power I know it can, fosgate is awesome, it's my sorry excuse for an alternator that is letting me down
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My alternator is rated at 145 amps according to Cadillac.
2088 watts to work with so you probably could get 1000 watts especially if you wire to 2ohms the amp is significantly more efficient at that "resting" load
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no. he's saying if you measured/calculated the impedance. if you're wired at 1 ohm, which im sure you are, there is no way in HELL your amp was sitting at 1 ohm during testing.
I agree with that however the measured power that the speakers actually see at 60hz frq is 460 watts, the impedance rise is not easy to account for without a different procedure the theory is the same my amp is never going to do its birth rms on the stock alt.
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I've got a t500-1bdcp on a stock alt w/ 2 bats I clamped it at 460w clean, at 1ohm it's sufficient for me. The birth sheet said 812 rms tho. What is your alt amperage 110? If so you have a total of 1440 watts to run every electronic component in your car give or take. So in my experience you might get 800 watts out of the power 1000. Efficiency of the amp at 2 ohms is about 80% so do some math and your amp will draw at least 1250 watts in to do 1000 watts out assuming perfect alt output and no loss in the wires. That's a long answer to a simple question which is the power 1500 and 2500 won't be able to provide any more power than the 1000. They are awesome amps tho I love mine.
so you clamped the amp and it did 460w at 1ohm? how exactly did you manage that. what is your sub wired to, did you get any impedance rise?
Ac clamp meter, 60hz test tone, and an Ac volt meter using the equation for power, P=V*I, I'm not sure what the rise was but I'm sure it happened, I did meter batery voltage at the same time and the voltage drop at maximum clean volume was about 1.7 volts (14.4 to 12.7), I blame my 90amp alt, it can't push enough current to support the amps draw, the amp needs to draw 75.13 amps to do the 812 rms watts which just isn't going to happen on stock electric haha
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To keep power output the same, the amp has to compensate by pulling more amps, which, like he ^^^ said, creates heat.
At least that's my understanding of it.
But then why does it do that?
Why what? Why does the amp try to keep output the same, pull more current or get hot?
P=V*I v being voltage I being current in amps and P being power in watts. If V drops I increases to keep the same power thus more current, current at a basic level, moving electrons generate heat. Wires get hot and that is bad.
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I've got a t500-1bdcp on a stock alt w/ 2 bats I clamped it at 460w clean, at 1ohm it's sufficient for me. The birth sheet said 812 rms tho. What is your alt amperage 110? If so you have a total of 1440 watts to run every electronic component in your car give or take. So in my experience you might get 800 watts out of the power 1000. Efficiency of the amp at 2 ohms is about 80% so do some math and your amp will draw at least 1250 watts in to do 1000 watts out assuming perfect alt output and no loss in the wires. That's a long answer to a simple question which is the power 1500 and 2500 won't be able to provide any more power than the 1000. They are awesome amps tho I love mine.
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box design:
total volume 3cu ft (after displacement)
dual 3in ports about 9in long with a 1/2 round over flare
custom milled trim ring hopefully wrapped in vinyl possibly painted black
the whole thing will be braced even though I doubt the amount of power will show serious resonance issues.
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I routed a half circle as far apart as I wanted ant then just cut out the part with a jigsaw and a fence
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bypass the fuse holde rand link the two ends of wire together. what does the end of the wire look like? Is it ring terminals or a push block style? Any corrosion on the wire? Is it turning green? does he have a cap or anything in the back of the car? extra battery?
X2
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Trusty router
custom milled trim ring
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You are 100% correct on all counts. But the cost was non negotiable so its going to have to work haha, I'm not proud but i ran a similar amp in my ride for about a year on BS 8 gage so I think it will be alright.
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Components: (pics soon)
Amp, RF R500-1D
Subs, RF R2D2-12
Front speakers, Pioneer TS-G1644R 6.5in
Head Unit, JVC KD-R530
Wires, DB link (smh) 8 gage (not CEA compliant)*
Custom box vented tuned at 34hz
*The amp can not draw more than 38 amps so the 8 gage wire on a 4ft run will be ok in theory but if it gets too hot I'll upgrade it to 4awg.
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I think that adding the extra length only helps haha I like it low so it definitely doesn't hurt.
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well i built my box with bent ports i think it sounds really good, it was a major pain in the ass though since i had to glue inside the box then hammer the port in through the opening so that good cement contact could be made. And instead of having 4 pieces i have 12.
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The problem, more than any of the others that occurs is high heat, when resistance is low and curent is high wires and amp internals can get really hot, so big wires and fans are a must especially for a daily system.
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if u just did online reaserch and then posted what u found, did you REALLY think we didnt know what we were doing? have u been around audio comps? most people are running below rated ohm load. y would audiophiles not know this
I'm sure everyone knows how to run at lower than rated impedance, I was try to explain why in semi technical terms, that people need more electrical. The vast majority of people on this forum can ignore my "moral" because like several persons have pointed out, "we already knew that" (that being of course you need a bigger alt and batts).
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Its actually because of a way higher current draw that causes voltage dip
Kthanksbye
Exactly higher curent due to lower resistance or higher load
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just wondering what made u want to write about this subject?
One of my friends was having this problem and nobody could explain why I was just told to get a bigger alt but I couldnt figure out why, so I looked it up an did some research
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Your correct but amp protection circuitry shuts down amps at low voltage so the amp turns off before amperage actualy becomes a problem
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So this is just a little explanation of why when we run at .5ohm it takes a big alternator or 2 and a few batts.
If anyone has ever had a 2ohm stable amp and tried to run at 1ohm without sufficient electrical they have probably experienced amp shutdown at volume, but most people don't understand what's going on electrically. The problem is called voltage dip, and it occurs when impedance is very low. As the impedance decreeces the curent increeces, and consistently voltage drops, the problem is literally that the impeeadece is so low the electrons are moving around the circuit so quickly that it's a near short circuit. And as most of us know the way to avoid this is to get a bigger alternator. The biger alternator can provide the curent the amp is asking for to combat voltage dip. The moral of the story is either beef up the electrical or raise your impeadance!
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You have enough power that you wouldn't need to worry about sub control sealed boxes if they are bigger can handle more power but if it was my system I would build a ported box at about 33hz and aim the sub in the traditional direction, I really prefer the sound of ports to sealed, better extension and if you pollyfill the box they have excelent roll off, I like to crossover at about 200hz btw
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sweet thanks for the help
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cool I figured but I wanted to see what you all thought/do when grinding
Why is low voltage bad for amps?
in Amplifiers
Posted
It will if it works correctly its more like the wires smoke, the amp should turn off if the voltage drops too low