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**kapone** · 10-04-2005, 12:11 AM

by the way most stock alternators spit out 60-80 ampers of power depending on model and features in the vehicle, batterys and caps DON'T create power they store it so adding batterys and caps don't help iff you don't upgrade the charging system in the vehicle ( the alternator) ...

**accrdpower** · 10-04-2005, 11:46 AM

Originally posted by kapone

by the way most stock alternators spit out 60-80 ampers of power depending on model and features in the vehicle, batterys and caps DON'T create power they store it so adding batterys and caps don't help iff you don't upgrade the charging system in the vehicle ( the alternator) ...

true true!!!! o guarentee most amp manufacturers state the amps put out so much power but it is not just power acoustic that will be less than stated. me thinks u do not like power acoustic

all good though, to each hsi own.

**bruno8747** · 10-04-2005, 12:12 PM

The thing I look for is CEA compliant. Atleast when its cea comliant you will know that your amp is doing its rated output. And its doing its rated output and then some most of the times.
All of the CEA amps I have seen put out more than stated on the box. Example I have an alpine MRD-301 which says 350 watts at 2 ohm RMS but when it came with the birth sheet it said 398 watts RMS at 2 ohms.

**deckeda** · 10-04-2005, 12:16 PM

Here are the rules of thumb:

1) When comparing power ratings and trying to get a sense of "how loud" an amp might go, look for sustained power, not short-term "max" or "peak" power --- means zilch. Music doesn't last for a nanosecond, it lasts for several minutes.

2) Without a switching power supply, no amplifier can make more than about 13w or so per channel continuously (with low distortion) on a normal 12v car system. Pretty much any head unit that advertises more (as they usually do) is marketing puffery.

X amt of power, into a particular ohm, per channel, at low distortion, continuously. Remove any one of those requirements and you'll get an inflated figure. This is the model home amplifiers must follow by law --- but for car stereo manufacturers it's only an ad hoc "suggestion".

**deckeda** · 10-07-2005, 06:58 PM

Originally posted by SteveB

... Power used is logarithmic in nature, and constantly changing in several orders of magnitude.

Good catch. I hesitated to write that; I should have re-phrased it.

My point was that many cheap amps advertise "peak" power; i.e. short-term power. Something more akin to how home stereos are rated, with continuous power, was what I was trying to encourage for those bent on shopping only by an amp's "power rating".

**JDMCB3Si** · 10-07-2005, 09:34 PM

Originally posted by kapone

as an example my fosgate amp is geting 14 volts of constant power with about 50 amps max, which means my amp will spit out about 420 watts to my subs,(its a class a/b amp) even though its claimed at only 50 watts x2 when it came out several years ago (its a punch 100 dsm)

OK so evidentally you didn't read up on the amp. The RF 100DSM put out 50x2@4 ohms stereo at 12.5 volts (which is what most batteries can give to the amp)The same amp at the 14.4 volts your claiming runs 100x2@ 4ohms stereo. Now unless your running it mono which is 200x1@ 4 ohms mono you are NOT putting out 420 watts per channel.

I used to have a RF 125.2. In ran 14.4 volts into it using an Optima yellow top coupled with a Stinger 170 amp alternator. I put out 155 watts per channel @ 4ohms stereo and ran 321x1 @ 4 ohm mono.

**kapone** · 10-08-2005, 01:16 PM

Originally posted by JDMCB3Si

OK so evidentally you didn't read up on the amp. The RF 100DSM put out 50x2@4 ohms stereo at 12.5 volts (which is what most batteries can give to the amp)The same amp at the 14.4 volts your claiming runs 100x2@ 4ohms stereo. Now unless your running it mono which is 200x1@ 4 ohms mono you are NOT putting out 420 watts per channel.

I used to have a RF 125.2. In ran 14.4 volts into it using an Optima yellow top coupled with a Stinger 170 amp alternator. I put out 155 watts per channel @ 4ohms stereo and ran 321x1 @ 4 ohm mono.

actually your right its not puting out 420 watts per channel cause i never stated that. I stated 420 watts to my subs as in total wattage and yes it is an estimate of what is the general amount of power being thrown out by the amp at any given bass note, oviosly their are more factors invoved with the phisics of amplification of an audio signal in the automotive enviroment. the perpus of this post was to provide a simple way to prove wether an amp is rating their amps corecly for real world use or just trying to sell you an inflated dream wattege... and yes by the way it is runing in a 4 ohm mono configuration (2 dual voice coil 4 ohm subs) and my estimate for the amout of ampers come from the fact that i keep blowing 40 amp fusses and i switched to a 50 and havent had any problems so i "asume" that 50 amps is the max the amp can handle right now ...like i stated its just a ruff estimate of the amount of power my amp is trully throwing out as opose to just beliving the manufacture ....

**mondojackal** · 10-08-2005, 05:00 PM

Originally posted by kapone

actually your right its not puting out 420 watts per channel cause i never stated that. I stated 420 watts to my subs as in total wattage and yes it is an estimate of what is the general amount of power being thrown out by the amp at any given bass note, oviosly their are more factors invoved with the phisics of amplification of an audio signal in the automotive enviroment. the perpus of this post was to provide a simple way to prove wether an amp is rating their amps corecly for real world use or just trying to sell you an inflated dream wattege... and yes by the way it is runing in a 4 ohm mono configuration (2 dual voice coil 4 ohm subs) and my estimate for the amout of ampers come from the fact that i keep blowing 40 amp fusses and i switched to a 50 and havent had any problems so i "asume" that 50 amps is the max the amp can handle right now ...like i stated its just a ruff estimate of the amount of power my amp is trully throwing out as opose to just beliving the manufacture ....

how old are you? j/w cause you dont seem to have a very good vocabulary..
not picking on you or anything, but if you preview your posts before you let everyone else see how you cant spell, then you might have a little more respect being thrown in your direction..
perpus = purpose
oviosly = obviously
phisics = physics
corecly = correctly
wattege = wattage
ampers = amperes (so many people dont get that one right though)
fusses = fuses
opose = opposed

btw, those arent even all of them, there are more..those just annoyed me the most..

**deckeda** · 10-08-2005, 05:56 PM

Ah, for some, it's spelling.

For others, capitalization and apostrophes!

**mondojackal** · 10-08-2005, 06:46 PM

you are correct, but, given that fact that i use punctuation, my typing is easier to read than words that do not exist!

**kapone** · 10-08-2005, 09:44 PM

you are corect about the spelling i apologise, my lack of spelling or my age has nothing to do with the fact that my original post was acurate ...if my spelling is the only thing you can find wrong please do me the favor ... the purpose of the original post is to educate the newer car audio guys and just novis enthusiast from geting riped of (power wise ) by inflated power claims by flea market amp companies ...

by the way ive been working on vehicles for 11 years now from car audio install to performance ...i dont consider myself the all knowligeble but i do know a little something about cars and im just trying to extend my knowlege to the less fortunate ...

**mondojackal** · 10-08-2005, 10:33 PM

Originally posted by kapone

you are corect about the spelling i apologise, my lack of spelling or my age has nothing to do with the fact that my original post was acurate ...if my spelling is the only thing you can find wrong please do me the favor ... the purpose of the original post is to educate the newer car audio guys and just novis enthusiast from geting riped of (power wise ) by inflated power claims by flea market amp companies ...

by the way ive been working on vehicles for 11 years now from car audio install to performance ...i dont consider myself the all knowligeble but i do know a little something about cars and im just trying to extend my knowlege to the less fortunate ...

oh im not dissin ya man..i just think it'll be easier to read if you did proofread it before you post it...'specially for them n00bs ur tryin to help

i agree with him though, you should always go by the 12.5 volt RMS rating. that is the most accurate rating that you can go by without actually getting the thing metered. many companies rate their amps and advertise them at their 'peak' musical power, w/e they call it, but the continuous power is what you will actually hear all the time. also, the 12.5 volts come from your capacitors and/or battery and the 14.4 volts come from your alternator, which, if you have a hi-output alt, is easy to come by!

**kapone** · 10-08-2005, 11:03 PM

the reason i use 14 volts is every car that i put a voltage meater on while its on reads that ...your vehicle runs of off alternator power not the battery the purpose of your batery is to provide power for your vehicle to start once that hapens the alt takes over trust me put a volt meter on your amps positive terminal and see what voltage it reads. it will be 14 volts if your alt is working properly ...

**mondojackal** · 10-09-2005, 11:52 AM

thats not true..indirectly..yeah, you could bend that thought to make it true..but its not true...
here's a great animation that shows you how that works..
Charging System

also, the battery feeds the stereo power not only when the engine is off, but when the power rails drop, and the alt isnt putting out enough power to supply the amps needs. the battery, or capacitors first if you have them, feeds the extra needed power to the amps, much as if the alt isnt even working

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