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Capacitors....
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=45&t=11979
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Author:  kolesy [ Fri Sep 01, 2006 6:31 am ]
Post subject:  Capacitors....

K, for all you car stereo heads out there. I am somewhat smart when it comes to systems and al but i never really dealt with capacitors before. I know I will need one since i am gonna have lights out the ars on my rig and was wondering what size capasitor i will need to run this amp. I have an optima red top battery and a 136amp alternator. So how many farads do you think i should need in a cap. Thanks!

Mike

Amp.. I will be pulling a 1 OHM load outta it too.

MA Audio HK401SX

Digital LCD Display (Voltage, Temperature & Output Level)
Platinum Plated Connections
Quiet Fan Cooling System
Top Loaded Power & Protection LED?s
Thermal / Short / Overload Protection Circuitry
0-18 dB Variable Bass Boost
40-250Hz Variable High Pass Crossover
40-250Hz Variable Low Pass Crossover
Remote Bass Control
THD @ 4 0hm <0.05%
THD @ 2 0hm <0.1%
THD @ 1 0hm <1.0%
S/N Ratio: >90dB
Channel Separation: 60dB
Frequency Response: 20-20kHz
Input Voltage Range: 200mV - 8V
Input Impedance: 10k Ohms
24dB Subsonic Filter (HK-401SX only)
1 x 500W RMS @ 4 Ohm Mono
1 x 650W RMS @ 2 Ohm Mono
1 x 1200W RMS @ 1 Ohm Mono
1 x 1800W RMS @ 0.5 Ohm Mono
Dimensions (H x W x L): 2.7" x 12.4" x 10.6"

Author:  sqliberty [ Fri Sep 01, 2006 8:35 am ]
Post subject: 

I think the thought is 1 farad per 1000 watts. I have a 1 farad in mine running 1400 watts rms with a yellow top and the 160 amp alternator. I too have a ton of lights and everything works fine.

Author:  JMLoughrey [ Fri Sep 01, 2006 10:08 am ]
Post subject: 

Ultimatly, capacitors are worthless if your charging system cant handle your stereo system as it is.

Yes, a capacitor has the potential to actually do more harm then good. If your headlights are dimming a capacitor is just a band-aid, and not one of those fancy medicated ones. It will hide the problem and chances are when it comes back, it'll be worse.

Read this link, it'll probably change your mind about wasting the money on a cap
http://wickedcases.com/caraudio/capacitors.html

Also, i'd say check your gain settings as its quite common for the gain to be used as a sub volume control, having your gain too high can cause your amp to clip the signal and start sending actual DC power to your subs.


*note, i do not have a clue what kind of knowledge you have about car audio, not trying to belittle you in any way, just trying to help*

Author:  Se7enLC [ Fri Sep 01, 2006 10:32 am ]
Post subject: 

JMLoughrey wrote:
Ultimatly, capacitors are worthless if your charging system cant handle your stereo system as it is.

Yes, a capacitor has the potential to actually do more harm then good. If your headlights are dimming a capacitor is just a band-aid, and not one of those fancy medicated ones. It will hide the problem and chances are when it comes back, it'll be worse.


I both agree and disagree. I haven't used a capacitor in a car audio context, but I have used them in a similar context - bypass capacitors for ICs. The purpose they serve is the same, to provide those short bursts of power that ICs (and amplifiers) need, without having to deal with the propagation delay and draw on the rest of the system.

If your electrical system is SERIOUSLY underpowered, I agree, buying a capacitor to "fix" the problem is a bad idea, as well as buying a capacitor if you intend to use the stereo with the engine off. In both of those cases you really need a better battery and alternator.

Dimming headlights isn't immediately a sign that the cars electrical system can't handle the stereo, though. It's just a sign that it can't handle the *instantaneous* needs of the car stereo. The average power needed is probably still low enough to work well, so long as you have a capacitor in there to level out the power needs.

But once you install a capacitor in there, now you solved the problem, provided that your average needs are still below what the car electrical system can provide. If you listen to a whole lot of bass for a long time continuously, though, the capacitor won't have enough time to charge (and the average power needed will be higher than what the car can provide) and you'll run into trouble,

Disclaimer: I don't know anything about car stereos.

Author:  kolesy [ Sat Sep 02, 2006 3:40 am ]
Post subject: 

Quote:
Disclaimer: I don't know anything about car stereos.


:-)r Hilarious!

Good words guys. I basically listen to a lot of Metal and hard rap, so as far as long drawn out bass notes, no i don't heave them. Everthing in my electrical system works fine now. But when I get back i am adding a lot of stuff so i figuered a cap would be safe to have. Yes it is gonna be there just in case i need it. I have heard that before somewhere as well, 1 farad per 1000 watts. We will see. I will probably going to go with a 1.5 Farad cap. As All the problems that article stated was when the car wsa shut off and music blearing. I hardly ever pound my system with the rig shut down. Thanks GUys!

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