Some info for people that use "capacitors" in car audio!

[Audiowizard]

There has been a debate in this forum about whether caps work or not so I thought I would make this a "sticky" in this forum. This is a direct quote from "me" from a conversation that I have had with a very good friend of mine this morning who is a world champion competitor in USAC & IASCA that is now using capacitors with his new set-up and says that they do work very well with amplifiers with unregulated power supplies. I feel this info will help people who want to run capacitors. This is purely simple information that I was given to me from someone that has used capacitors in the past and will be using them again now for next years USAC & IASCA events!

Originally posted by Audiowizard
had a long conversation with Gary Biggs this morning about getting our families together this weekend and of course the topic of "capacitors" came up! Now to answer the question of why Gary wasn't using capacitors in his Buick this year!...........

Gary was running Kicker ZR amplifiers with "regulated" power supplies so the use of capacitors would not have bennifited as much in this application............

Now here is the funny part!......... For next years events, Gary will be running a crap load of "capacitors" (Yes, I did say capacitors) with his new Kicker KX amplifiers with "unregulated" power supplies where the "capacitors" will be doing their work to help supply voltage to his numerous amps and high output. Since the new rebuild on his Buick has not hit the C.E.S. show, I am unable to publish the number of capacitors and farad ratings per his request but the amount and the power that he will be running is astounding!

My whole point for this post is to let everyone know that capacitors do work dispite of what has been said negatively about their use in a previous post and they work very well with amps with "unregulated" power supplies (the more voltage the amp gets, the more power that they put out). Now amps with "regulated" power supplies dont benifit as much and will not hurt performance to add them if you so desire. This information comes from a man who is one of the top competitors in the country and is there because of his vast knowledge, experience, and dedication. If anyone would like to email him directly about anything concerning car audio, feel free to email him at............

gbiggs@kicker.com

 

[Audiowizard]

Here's some more info from another post.............

Originally posted by KendallF
Caps in a power supply, whether external in the line to the supply or internal as a part of built in regulation, are there to provide just what Audiowizard says: current to support transient (short lived) demands. If you have the alternator and charging system from hell, the need for them lessens somewhat.

An alternator's response speed is still going to be slow compared to a cap (probably 100s of ms. versus a few ms.) so if the amplifier's regulation isn't sufficient, transient response will still be improved with the addition of a capacitor.

If the amplifiers have heavily regulated power supplies, part of what this means is that they've put more capacitors inside (that's a simplification, but still true).. Even a regulated power supply will "de-regulate" when the input voltage drops to a certain point; so you need batteries and alternators capable of keeping up with the average or steady state demand.

 

[Audiowizard]

Here is a post from Mark Eldridge from carsound.com about the benifits of using a cap.

Originally posted by Mark Eldridge
Hey guys!

The only amp that will need the cap is the sub amp. Midbass, midrange, and high frequencies do not require nearly as much transient power as sub bass frequencies do to be accurately reproduced.

Also, a fuse between the cap and the amp will totally negate the effectiveness of the capacitor. If you have a fuse between the cap and the amp, then you have spent a lot of money on the cap and the installation for nothing. This is also true if you have more than a couple of feet of power cable between the cap and the amp. The impedance presented by the wire negates the effectiveness of the cap. And, it doesn't matter how big the cap is. The impedance(s) caused by long wire, a fuse, etc is (are) in series with the capacitor. A high impedance prevents the cap from providing any benefit.

And, some of the very expensive "very high capacitance" capacitors on the market have such a high internal impedance that they can not provide any real benefit, regardless of how they are installed. Go figure...

If you want a really good explaination of why this is true, get the Autosound 2000 Tech Brief article titles "How Long is a Piece of Wire?" written by Carl Miller. Look in the index for Inductance, wiring. (If you have the complete back issues of the Tech Briefs, it's on pages 483-484.)

So, basically, if you want to have your capacitor be most effective, Make sure it has a very low internal impedance (ESL and ESR), mount it as close to the sub amp as possible with as short a wire as possible, and install the fuse BEFORE the capacitor. If you've got two sub amps, and you wnat to have capacitors and fuses on both, you'll need two capacitors.

 

[IrvJr]

I think i need a cap, so how do i know what size to get. I have never used one before?

Scott

 

[Crazi]

The general I saw in my research is .5 farad is the minimum you can get so get that unless your system puts out 1000 watts or more. I think the rule is .5 farad per 500 watts or something. Now when I installed my cap, it didn't help with the lights dimming, and didn't help with the sound of my system that I can hear any way.

May I shoulda got the whole 1 farad instead of half...

 

[IrvJr]

OK,well what helps with the lights dimming?

Scott

 

[Crazi]

LOL, I'll tell you when I find out. I did a bunch of research and found that the amp is demanding too much current for the Alt to keep up immediately. I upgraded to the 140 amp impala alt and it is still there. The voltage drop is less though. My stock alt was at 12 -12.8 volts and would drop to high 11 during bass hits or idle with lights and crap on. The 140 amp idles at 13.5 or higher and drops to high 12 rarely on bass hits.

To stop the dim lights, what I read is you need a second battery in the trunk or move your first battery to the trunk. But I don't compete with my audio in the least so I can't justify that.

 

[IrvJr]

I dont compete either, but its very noticeable at night. I hear that its bad for the alternator. Could it be the amp is too old? Ive had it for over 10 years, its a Coustic 360. Its only pushing 150 watts to the 1 12" Pioneer sub. It hits good, butithought maybe the amp was to old for that kind of duty (I said doody).

Scott

 

[Crazi]

Very noticeable like almost turning on and off or just a dim that you can see if you look at it continously?

Mine is the second and I just live with it after I changed the alt and it helped but didn't go away. If yours is the first, do you have a way to check your alt? I would even say go ahead and get the impala alt if it is in the budget.

One other question. What kind of wire do you have running to your amp? I have like 12 gauge I think and I keep reading that it is too small but I don't feel like changing it. Maybe I will run it outside the car direct from the batt to the amp and see if it helps first. If you wire is smaller then 12ga, then you NEED to upgrade.

PS

I should be running 6 gauge wire.

 

[IrvJr]

Its not quite as bad as turning off, but very noticeable. I have 4 ga running from the battery to the trunk to a 4 way power block. Then it uses whatever comes off the amp, it has short leads.

Scott

 

[Crazi]

Damn!! And your lights are dimming? Ok what kind of battery do you have?

Another fix is to run your headlights off a relay instead of the factory switch. I did that upgrade too when I switched to Cool Blues. Other then that, a new alt and battery are all that I can suggest. I got the largest battery that would fit which is 800 CA Duralast Gold or something like that. That is from Autozone too.

 

[IrvJr]

The alt is new, less than a year. Battery is a Power Force, 775 CCA, also less than a year. Is it possible its just an old amp, and i should upgrade it? Did running your headlights off a relay help with the dimming, and how do i do that?

Thanks, Scott

 

[Crazi]

Could be the amp but I don't know. I cut the feed for the power to the drivers headlight and hooked that up to turn the relay on. Then ran 12 gauge to the battery and 12 gauge to the light. Ground the other side of the relay and you are good.

I wanted to rewire the whole thing but never got around to it. It made my headlights brighter but they still dim enough to notice, just not enough to worry about.

 

[GNandTTA]

I would check the ground. I would also upgrade the grounds. You can have the biggest power wire you want, but it don't mean jack if your ground is the weak link in the chain. Upgrade the ground that goes from the battery to the fender. An even better solution is to put a 4g ground wire from the battery to the frame rail. A good spot is the bumper support. There are 4 big bolts there. Get a big ring and connect it there. You then need to connect (bond) the trunk to the frame. There are 2 holes in the frame right by where the exhaust pipes exit. Again, big bolt and big wire.

 

[Crazi]

Hey that is a great idea! I added an extra ground wire from my battery to the body but never thought about the frame. I figured everything grounds through the body so I didn't even think about the frame. And my ground wire at my amp is probably 14 gauge or so but is only 6 inches if that. I'll upgrade that too.

 

[Audiowizard]

Originally posted by Crazi
And my ground wire at my amp is probably 14 gauge or so but is only 6 inches if that. I'll upgrade that too.

Your ground wire needs to be the same gauge as your power wire so if the amp reguires a 8 AWG power cable then the ground must be 8 AWG. Body grounds on these cars are terrible for amplifiers so ground directly to the frame with a bolt and star washer on a clean bare metal surface. That helps to prevent ground loops which induce motor noise.

 

[IrvJr]

I also ran a 4 ga ground to the body, it goes to a 4 way splitter as well. But i will try the extra grounds, i do have engine noise as well.

Thanks, Scott

 

[8UWITH6]

I have a question about regulated vs unregulated amps. I run a Punch 200IX old style Rockford and a Punch 40x2 old style Rockford in my Ttype. Are the old "good" Rockfords unregulated? Also, I have a Rockford 1 Farat Cap, have used it for over 3 yrs now. Didnt notice a difference really, but I didnt see what could hurt putting one in. Just wondering..........

Also, on the grounds, I just ran my 4 gauge grounds to the trunk floor, cleaned the paint off and used a self tapper. Im ASSuming this is not efficient enough? I know your grounds need to be as short as possible, so I ran it straight out of my "sandbox" that holds the amps, blocks and capacitor, to the closest part on the trunk floor. Any suggestions there? Thanks fellas

 

[mcss383]

Well the whole 'unregulated vs regulated' is just marketing, all car amps have regulated power supplies. What they mean to say is a tighty regulated or loosly regulated and all that means is with a tightly regulated power supply the amps power output won't change AS MUCH as a loosly regulated version. Not sure about the old RF's, but I want to say that they are tightly regulated.


For your ground I would just get a small bolt and bolt it. The only other 'upgrade' you could really make is to run your ground to your frame (and do likewise from the battery), but thats not really needed, chassis is just fine.

 

[intercooled84GN]

altenator

If your lights dim to the bass,a cap wont help near as much as a high amp altenator.Believe me,they make altenators big enough to keep your lights from dimming,but they are expensive.To get a high amp altenator cheap,go to the junkyard and get the biggest one you can find.Like a cadillac with ALL the options.That altenator will be a beast!