So, I'm familiar with what a cap does, but I've never had or used on in a car system.

I'm soon going to be adding a set of Diamond Audio Hex's, with an amp running at 150 watts per channel. Later I'll add a 10" sub, with another 300-500 watt amp.

Looking around, one sales guy today was pushing HARD to tag a cap onto the sale. Honestly, I don't know if it's worthwhile.

Can somebody in the know enlighten me a bit on how necissary a cap is? FYI, the one in question is 1 farad and runs $170.

Thanks,
Jason

 

If you want it simple, when you hit heavy bass (or any part of the music that takes more sudden power) it will be like the the amps ran out of power and the crispness of the music will suffer. I personally would put one in, but you could always add one later if its an issue... espessally w/ the sub. $170 is really steep for a 1 farad FYI.

 

I got my 3 Farad Cap for $119 @ etronics.com

You do not need a cap for anything under 500 watts unless you have a cheesy alternator like in a Geo Metro, ect.

The rule of thumb; is for every 500 watts, its a 1/2 farad cap.

I have 1800 watts and I also have an optima yellow top battery. I have no problems at all.

I would not pay $179 for a 1 Farad Cap unless that price was installed.

 

Capacitors are incapable of holding enough energy to sustain any sort of meaningful output. They do, however smooth the "peaks and valleys" of the current made by your alternator. It's not worth $170.

 

Caps are not meant to sustain power for any length of time. They are there to stiffen up the power supply when you hit a big transient. They provide power only for a short burst at a time.

But I agree with the above posters, unless you are running over 500 watts AND listen to your music LOUD you don't need one at all. A healthy car battery can supply a butt-load of current VERY quickly since it is designed to drive a starter motor.

You can build the system, play it loud, and then decide if you need the cap. It could save you $170 in wasted money. If the lights dim on heavy bass notes you might need one. They easiest way to check is with an analog volt meter. Just watch the voltage at the battery. If it dips a lot on heavy bass notes you might need the cap.

 

Okay guys, thanks for the help. Since I'm going to have 300 watts running right now, I'll wait until I get a sub and sub amp (another 300-500 watts) before getting the cap.

 

i bought a 1F lightening audio cap that i never used after installing a jl 300/4 and a jl 500/1 running on focal 165V and jl 10w7....everything is running fine even with heavy bass hitting. no dimming, no drop in voltage when volume is high.

i have the cap brand new if you want it. 50 bucks for the lightening strike series digital 1F cap. I dont have the charge card, but any decent stereo shop would know how to properly charge it.

but like they said above, it can help, but not absolute necessary until you get up there in total system wattage.

 

I have got a 1 farad Lightning Audio cap I bought for $150 installed, I'll sell mine for $50 also.

 

Okay well, maybe I'll never need a cap

I decided on a different, and definately much more high end shop. They believe that even with a JL 300/2 and 500/1 I won't need a cap, but might want to consider a Optima battery.

 

This is because the JL audio amps have a fully Regulated power supply, putting a cap in line would be redundent. Optima however is a good idea in any system.

Nazar

 

I work with a seriously talented electrical engineer. I asked him about car stereo caps. (I have a minor in EE so I can talk to him about this stuff)

His opinion was that you would need to be drawing a LOT of power to need a cap. TONS of power.

He said a car battery is capable of VERY high currents particualrly in short bursts. If you had a clipping problem it would more likely be do to undersized wires or bad connections.

He follows the "loudest stereo" competitions somewhat (mostly to mock them) and he said the capacitors came out of the competition circuit where cars with thousands of watts are not uncommon. He also said that lots of people assumed that if the pros use them they must be necessary.

So, based on his input my opinion is that unless you hear a problem, measure a voltage drop, or see your lights dimming to the beat then you probably don't need it.

 

Power Capaciters are very usefull with Unregulated amplifiers. The reason behind this is, an unregulated Amp will make more power when ther is more Voltage. If the voltage drops well less power. So If you have a Subwoofer you will notice bass notes are when the amp is working th ehardes thus dropping the Voltage. So if you have a cap in line it would help that voltage drop stabalize to a certain degree. Ofcourse you need to make sure your Alternater is up to the task.

Alternator still needs to be able to charge the Caps. If you have a 80amp alternator a big system, let's say a big Rockford 1000Bd and 3.0 Farad caps. Well you get the picture. You will eventualy have a dead battery, Because the alternator will not keep up with the demand.

Tried to put it in simple words.

Nazar

 

Nazar, I'm confused, you are saying I will have a dead battery.

Hmmm: Optima Yellow Top, 3 Farad Cap, thats not enough for my system?


On another note, do you know of any compustar alarm dealers in the Springs?

 

No, No, No... All I am saying is. If you have a NON-Regulated Amp and in your case I believe you have a JL amp which makes your amp regulated.So you are Allset.
But If you only had Caps, a powerfull Non-regulated amp and a charging system not up to par, let's say with listening habits at full volume all the time, when you are at idle. The alternator will not keep up with the charge. Optima or any other deep cycle battery like the Rockford Fosgate and Lightning audio Batteries are always a good idea if you are planning on a stereo system period. Just for the fact you can kill them and bring them back to full charge repeatadly. This is in case you have an 80 amp alternator like in a 87-88 Mustang.... This was a hypothetical scenario.
I believe the alternator on the 350z is a lot better rating.

 

Ok, how about that compustar?

 

Can somebody describe the difference between a regulated and un-regulated amp?

 

In simple words.

Imagine a 1000 Watt Amplifier.

A non-regulated power supply in an Amp will give you more power as the voltage goes up. Such as at 12 Volts it will be 500 Watts and at 13 Volts it will be 700 Watts and at full 14.4 Volts it will may be 1000Watts or above like 1100 Watts at peak.

Versus a Regulated power supply will give you the same power no matter what between 11 Volts to 14.4 Volts. So weather it is at 11 Volts or 14.4 Volts it will always Give you 1000Watts

Hope this helps