Printer Friendly Forum Posts - Capacitors....worth it?

Hey everyone,

Just found this site and just from reading a few of the threads looks like we got quite a few people here who know car audio. First a little info about my system that I have. I have a JL Audio 12w0 in a truck style wedge box (only thing that fits in my truck sadly .... bah) anyways I just picked up a Lightning Audio B300.2 amplifier to put on it. I am wondering if the amp itself will be enough, or should I go ahead and get a capacitor as well and throw that on there? How much do they help the sub? I personally like my sub to BUMP, and it wasn't doing a good enough job with my old amp (an MTX 120W RMS amp). I am thinking the new amp will be good, but I have heard that a capacitor could help. So my question is do you think a capacitor is worth the money and will it make that much of a difference ? Thanks!

Well the cap will not make the sub any louder, it will help with peaks in your music as far as your amp goes...I dont think you can go wrong by anymeans getting a cap...depending on how much power your pulling you might not really need it...how much bigger is your new amp?

thats my thoughts on a cap,

good luck

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If we learn from each success and
each failure, then we can improve ourselves

Old amp = 120W RMS bridged..... New Amp = 300W RMS bridged .... but I will also be running both amps now too...old amp is gonna go to the door speakers and the new one to the sub. So a capacitor basically helps when you need an extra boost to the system is that how it works?

you wont need a cap.

if your total power was approaching 1000watts then definately but you wouldnt notice at this stage.

someone else will correct me if i'm wrong but i think the rule of thumb is 1farad capacitance for every 1000watts. most caps are 1farad or larger these days.

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2001 Ford Fairmont
Alpine DVD, screen,
5.1surround processor,
5ch Class-T amp, TV tuner
and centre channel.
Focal 3way Utopia splits.
VDO navigation. Stinger cap.
Soundstream Exact subs.

Yes, that is how it works, it stores energy until it is need then it supplies the amp with the energy that is stored, then it recharges itself, something to that effect....

And a good rule to go by is a 1 farad cap for every 1000 watts and .5 for 500

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If we learn from each success and
each failure, then we can improve ourselves

eargasm wrote:

you wont need a cap.
if your total power was approaching 1000watts then definately but you wouldnt notice at this stage.
someone else will correct me if i'm wrong but i think the rule of thumb is 1farad capacitance for every 1000watts. most caps are 1farad or larger these days.

he is correct,

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If we learn from each success and
each failure, then we can improve ourselves

alright sweet thanks guys....well I will have to see how the new amp sounds tomorrow and go from there I guess....I really wish I could get a bandpass box in my truck, but not enough room *cries* haha

Good Luck with everything

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If we learn from each success and
each failure, then we can improve ourselves

Man...if your lights on your car are dimming..get a cap. If a cap doesn't help you need to upgrade your electrical system.

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~The Rookie~
Rookie of the year that is...
Don't let the smoke out of your equiptment..it doesn't go back in.

Your JL sub only likes about 125 watts RMS. Feeding 300 would be feeding what it can handle peak. If you want more bump buy their W3v2 12 or something. I know the W3v2 12" likes 300 watts RMS so it might be somethin to consider.

as much as I would love to get a better sub....sadly this was the ONLY one that would fit in my box that I had. It is a really weird design and really shallow mounting depth, and we actually had to throw a spacer in there just to get the sub to fit. So if I could have I would have gotten a better model, but rumor has it that JLs rate their products VERY conservatively and can handle a lot more power than what they say. Hell my buddy has 2 12w0s in a sealed box in his eclipse and he is running about 300w RMS to em and they bump, so I figure mine should do okay

Sorry I disagree guys, It's sound like your useing a Stiffining Capactors as a band aid. The first thing any good installer should always do is beef up the complete chargeing system, get the biggest Alternator in AMPs you car afford. Run bigger gage wire, better grounds. Your System will love it and sound great. (run cooler, cooler amp= better sound, ) If you still need a Stiffining Cap or two or three then put them in. but not until you do the basics.

Hope this help,

Julian59

Uh and dont forget that every single component (read: cap. amp. cable. is a load on your system. Get a calculator and Ohms law. See you... Mel

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Someone pass me that bottle.

Whoever said "band aid' is right on in my book. I have always believed stiffening caps are a waste of money. They do more to make a user believe they work that do they really help in increasing net voltage to an amplifier. Indeed, I've done tests where the added load of the cap on a car's system actually hurts more than it helps. If your car's electrical system cannot handle the load of your system, install a bigger alternator and upgrade your wiring. That is the only way to really improve the voltage stability of the car.

I agree with DYohn, a cap is not a good idea. You should be good with your current set-up but if you want to do an upgrade you will want to look into getting an alternator upgrade. If your alternator can not keep up with your system a cap will not help, it will actually hurt your system. A cap is for quick notes not continuos loud playing. If you play your music loud for long periods you will want to upgrade your alternator. If you add a cap you risk the possibility of your system running out of juice when playing your music loud over periods of time.

DYohn correct me if I am wrong, but I have had the experience of playing my music loud with my car running and only to have my system to shut down because my cap ran out of juice. I am running about 1,100 watts RMS and a 3 farad cap. This problem never occured before installing the CAP. Duplicate problem occured in a different system running over 1,500 watts using a CAP. The removal of the cap fixed the situation of the system shutting down but created the problem of heavy dimming lights.

Yes, a large capacitor like that can actually shut down your car - or blow out your alternator or voltage regulator. What happens is after a large transient where it discharges, it will immedialtely try to charge back up to its normal voltage and will draw as much current as teh system will allow. This can add such a large load on your car's electrical system that the cap will overload the car's electrical system by itself. With multiple quick "hits," the continuous cycling from the cap recharging at max current will also add extreme loads and stress on your alternator and can lead to premature alternator failure. I have also seen amps shut down on low input voltage each time a large cap tries to recharge. Like I said, more harm than good.

Dyohn, I know that caps were for instant peak music over short periods of time but never took the time to analyze the entire situation. Now that you have put it in perspective I think I will have to get rid of the cap and replace it with a DVD player and upgrade my alternator.

I dont think you need any upgrading. 300rms wouldnt do much at the max to the electrical system. If it somehow does, firstly up the wires going to and fro the alt with way bigger wires. That'll help the flow. If that somehow doesnt do it. Look around on ebay and get a high output alt. They are relitivily cheap there.

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would just a .5 fared cap in a Ford Escort without a high output alternator and a Rockford amp runnin 500 watts RMS help at all or just cause more trouble? Right now the headlights dim pretty bad:(

Yes, it'll definitely help.

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My ex once told me I have a perfect face for radio.

You probably aren't pulling enough watts to need a cap, but if you have a problem with dimming headlights you should get one. If not, I would,t worry about it. And yes they are worth it if you need one!

You don't pull watts, you pull amps, you hear in decibels, wattage is a byproduct of voltage x current and will not tell you how loud something will go or how it is going to sound.

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Top Secret, I can tell you but then my wife will kill me.