# Where is my alternator output wire

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thanks for that.

#### UrSv

Mach_Y said:

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Long story short... a capicator on the power line to help with bass notes is pointless. Typical voltage of a car when the car is running is around 13.7 volts. All the caps out there are 12 volt for cars. The cap won't begin discharging its energy until the voltage drops below 12 volts. Additionally, due to the ESR of the caps, the caps cannot release their energy fast enough to be of any use to the amp. If you already own a cap for a car, it will do much more good for you if you install it next to your headlights rather than in your trunk with the amps. If you want the doctoral math behind all of this, look at Richard Clark's forum:

http://www.carsound.com/ubb/ultimatebb.php?ubb=forum;f=1

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Why would it not supply power until the voltage drops below 12 V? Is is not like any other cap i.e. charged to the voltage to which it is connected, in this case 13.7 V and thus supplying power when needed=all the time? The 12 V rating is just a rating and furthermore aren't most of the rated to take 16-24 V rather than 12 V? This again is just a rating. And ESR is usually VERY low eg 2 mOhm giving 1 V internal drop for 500 A. I'd say that would help quite a lot compared to the cable impedance.

#### Mach_Y

UrSv said:

Why would it not supply power until the voltage drops below 12 V? Is is not like any other cap i.e. charged to the voltage to which it is connected, in this case 13.7 V and thus supplying power when needed=all the time? The 12 V rating is just a rating and furthermore aren't most of the rated to take 16-24 V rather than 12 V? This again is just a rating. And ESR is usually VERY low eg 2 mOhm giving 1 V internal drop for 500 A. I'd say that would help quite a lot compared to the cable impedance.

*nods* if I remember correctly, it has to do with the internal power supply of the vast majority of amplifiers buffering down the input voltage to 12 volts. On the link I posted to sounddomain, do a search for capicators. Richard Clark had a very long post with the math behind why a cap external to the amp on the power supply line can do nothing for the music... it can do wonders for dimming lights though. The main point was the speed at which a cap can release energy being not anywhere near fast enough for music.

#### CarMan

Well I've already replaced the 3 magic wires, and forgot to mention that in my previous post (sorry!). It's all four gauge. I still get major dimming in the lights. Like I said, the amps are rated to draw 95% of my alternator's current. I thought people would pay attention to the current draw off of the amps, and maybe should have stressed this more. I lapsed in memory, forgetting that most people don't draw more than 80 amps, in which case switching the 3 magic wires should generally solve to prob.

Those amps that have a 12 volt rating and a 14.4 volt rating don't have the downbuffer, do they? It wouldn't make sense to rate them at both voltages if there is regulation...
The only musical claims I have seen about capacitors is below 100hz. Don't know if it helps any though, as I have not heard a difference and I have a pretty good ear. Most amplifiers carry thier own internal capacitors for sound quality.

Is it good to connect the cap directly to the battery with as short a cable as possible, or should I make sure to connect it in line to the lights I don't want to dim? I didn't think the placement of the cap mattered as long as it is connected directly to the battery, but you guys say it does. What do you think about putting another battery by the amps? This would help supply current, right?

#### UrSv

Mach_Y said:

*nods* if I remember correctly, it has to do with the internal power supply of the vast majority of amplifiers buffering down the input voltage to 12 volts. On the link I posted to sounddomain, do a search for capicators. Richard Clark had a very long post with the math behind why a cap external to the amp on the power supply line can do nothing for the music... it can do wonders for dimming lights though. The main point was the speed at which a cap can release energy being not anywhere near fast enough for music.

I'm no Car Audio expert but the way I get it is that the rating of most amplifiers is at 14.4 V instead of 12 V and that it is not buffered down to 12 V. Why would you dissipate those 50 A times 2.4 V as 120 W heat when the most important thing to get any power out of these amplifiers is to keep the supply voltage as high as possible? As for not helping for the music that makes as much sense as changing to 6 V batteries for your car. None at all, IMHO. Without reading his explanation I'd say Richard Clark is incorrect.

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