I had a 12" Rockford Fosgate HE2 sub and I kept blowing it every time I got a new one. I didn't learn until after the 3rd sub I blew that the gain on my amp was cranked to the max and as a result my sub was loud, but was sent a clipped signal by my amp. Now I have 2 10" RF subs and the same amp but with the gain down. I was wondering if I were to get a 1 farad Cap, would I be able to turn the gain back up a bit (not all the way, but up) with out sending a clipped signal to my subs? My friend told me that a cap would help out with the type of signals that were sent from my amp to sub so that is why I was wondering. Thanks.

 

Your friend is correct. You should find a stereo shop woth an oscilloscope to properlly set the gains in your system. They can read the signal on a screen and set it just below the clip.

 

the cap can help it out..but are you pushing you subs that hard? Or..what amp do you have...it could be because your amp is not powerful enough to drive the subs to their max. excurision.

 

My amp is a Kenwood Excelon KAC X401M. It has a peak power rating of something like 1000 watts, so I don't think I have a lack of power. It pushes my tens just fine.

 

what ga power wire are you running..and how big is your ground?

 

Im using 4 guage wire for power and ground

 

I really don't see a cap solving a blown woofer problem. And that is an old amp so I don't have specs for it. If the amp is of any quality, it should shut off with low voltage, so should not be able to send a high amperage signal to the subs. You may have the gain too high, and you may not have a sub that can keep up with the amp. You also may not have the sub in the best enclosure for the power the amp can provide.

 

My question about the capacitor was that if I got one, would I be able to turn the gain up? The reason I blew my first sub is because the gain was to high so i turned it down but I just wondered if getting a cap would better distribute overall power, thus allowing me to turn the gain back up a little.

 

Adding a cap essentially will regulate your input voltage. Levelling out the dips. And having more power for the amp to draw will not be a good reason to raise the gain, rather maybe the opposite. If you blew your sub you either have too much power going to it, a distorted signal, or both.

 

also, have you upgraded the battery to ground, the battery to alt, and the alt to ground wires? that will help out so you dont get so much voltage drop, and wont cost you as much as a good cap. and anyway, caps are just bandaids, they dont fix the problem, they just cover it. trust me, i have one.

eric

 

I haven't upgraded anything like that. I have a Nissan battery, stock alternator, etc. I'm running 2 10" subs with an amp that runs about 300 watts to each sub. I didn't think I had a very powerful system, but my interior and exterior lights dim just the slightest bit with it on. I was just wondering about the cap to see if it would distribute power better, and not send as much of a clipped signal to my subs as it was before.

 

if youre getting dimming, go for the wire upgrades first. 300 each is still quite a bit. i know a guy that was running about 5-700 watts to 3 10w6's, and melted his ground cable. the factory stuff just isnt made to handle that much power, so you should do the wire cuz its cheaper, and will probably do a bunch more good.

eric

 

ground wire is the first thing to do when "beefing" up a system..then comes a Cap..then a upgraded battery..then comes the dual battery/alternator upgrade

 

im sorry, but i disagree. you cant be fixing power (the dimming) without more power coming in. the wire should come first, then the alt, then battery, THEN cap.

eric

 

capacitors spread out the power, its like a storage tank, so i dont see how you get it sending more power (besides to the subs themself), actually a capacitor will make everything from the battery side of the cap run smoother because it will have a constant flow of electricity vs. the changing one because of the subs.
MrGone

 

umm..no..i think your wrong...according to..me..MECP..and several of my teachers..who even judge USAC sound events. Logically if you look at it...So...you've got the beefy wire..your alternator is charging the battery under your hood....then you upgrade your battery . So..you've got beefy wire...a beefy alternator and a good battery. So what..every hard hit of bass will still hafta come from 12+ feet of power wire to the front of the car....then it draws it from a BATTERY!....Batteries are made mainly to start the car..Optimas are special..being deep cycle (able to discharge fully and recharge w/o loss of electryolites). A starter draws current rather slowly compared to a hit of bass which can draw 100 amps in an instant. A capacitor is designed to charge and discharge very rapidly...Thus making it the 2nd step in upgrading your systems power supply.

 

well, for the record, i have a cap. it is just a bandaid. you must have enough power, before you can provide that power.

ill humor you for a minute, but i need you to explain something then. if you have the cap, it will fix small amounts of voltage drop, but that stops when it cant get power. how do you fix that?

thats what the alt is designed to do. it provides power to supply the system, and if its too small, no amount of caps will fix that. if you increase the ability to supply, it would not choke the voltage on the amp, causing less dimming. ???

eric

 

btw, im sorry, but i dont think that mecp really proves a whole lot. there are a lot of mecp people working at cc and bb, and very few of them can correctly install a stereo.

here is a graph to show my point. this is measurements taken by richard clark:


eric

 

Telling you this straight out, if u got a cap, no you couldnt turn your gains up because of that.

 

lemme break this down for u MECP person, when your upgrading your charging system, this is after all the neccassary wire is installed, the alt is the most important, it supplies power to EVERYTHING, when the car is running, batteries do not power hardly anything, neither do capacitors, the alt gives out a higher voltage then the other devices... though a capacitor releases its input voltage, which is usually lower then the alt because there is a small inherent voltage drop when running DC voltage through wire, no matter the thickness... so, the only way to get power from the battery or the capacitors is to lower the voltage of the altenator to below 12ish volts, thats the batteries charging voltage, actually its usually higher, bla bla bla, doesnt matter, and the only way to lower the altenators voltage that much is to draw more current then the altenator can give out, make sense?? so.... one should get an altenator that can supply the entire system so as not to have a voltage drop that bad, then, comes the battery, the battery should compliment the altenator, so to have a longer battery life, for more reliable starting, which is all the battery really should do, unless your in some ungodly high power setup for competition, then i dont understand that enough to know why they compete with walls of batteries, then, the capacitor, mainly for looks in my honest opinion, you shouldnt need one if your other electric components are in good shape, alumapros biggest capacitor is inherently useless unless the voltage drops to around 10-11 volts i have heard, and if you have that much problem with your charging system you shouldnt run a system, so, basically thats my speel on charging systems, capacitors arent needed, or even useful unless you have the tiniest amount of light dimming... so everyone, before you spend that 100 bux on a 1 farad cap, save up a lil more and upgrade the alt
whew

 

now to help you out... the capacitor has hardly anything to do with a clipped signal, pretty much, i would definetly find a shop to set your gains with an osiliscope like mentioned earlier... after that, we can come up with ideas to get your system louder with the exact same amp subs and ect... first, tell me the exact type of subs you have, what type of box.... and we can work with that, your amp is rated 400 watts rms at 12 volts, and 600 at 14.4 volts, both at 2 ohms, so... i know that, but, i need to know what subs your working with, to find out what box would best work with them, tell me, and i am more then willing to help, also, listen to eric and get your underhood wires upgraded, later

 

I have 2 Rockford Fosgate HE single voice coil 10" subs. I have them in a sealed box.

 

As someone who has installed a HO alternator in my maxima let me tell you that it is a waste if you don't have at least 3000 quality RMS watts. The stock alt in the Max puts out roughly 110 amps, compared to a civic with 60 amps. A cap is way cheaper and more benefitial. A cap is a bandaide, but one that is very effective. Because the voltage drop depicted in the above graph is the drop before the cap, not after. If it is after then Richard has thrown one of his typical curve ***** that ends up confusing everyone and proving the point, but leaving the majority misled. What I mean is that Richard sets up a lot of tests that are designed to fail for one specific point. And the point used above is not the point he intended, so the data would need to be analized to relate to that point. The only time that you have a voltage drop with proper wiring is for a very short burst. Unless you are competeing and running long, high SPL bursts. The stock alt is plenty for a high power daily driver. As said above, it is only used to start the car. So unless you sit in the parking lot with the engine off for expended periods, keep the stock battery and alternator. The people above also forgot to mention that a high power alt also has more noise than a stock alt, so one more problem associated with the install. But I highly suspect that the cause of your light dimming is low quality amps with poor power supplies. As I have never seen a Max with dimming lights, with or without cap. As another example I will use my wife's car. With an MTX amp pushing 300-500 watts at 12.5 volts she had no light dimming in her VW. But with an old PPI amp, roughly 200 watts RMS, she had considerable light dimming. Everything else was the same. So low power systems can drain the electrical system if they are poorly designed. But a cap can stabalize the voltage, where an alt can not. Remember, the alt doesn't even turn on until after the voltage drops. And the power from the alt goes to the battery first, then through a long cable to the trunk where you distribute it however you want. Also remember that the people who wrote the article in the recent Car Stereo Mag are trying to sell alternators, so you have to read the article with a little discretion.

 

Well, i drive an accord, and i know hondas a lot better then Nissan's, so i was unaware that the stock alt is 110 amps, pretty dern good in my opinion.
The voltage drop shown in the graph is before and after the cap, as you can see, they are nearly identical, so, where does the cap help??
I honestly dont know much about amps and powersupplies, though i would consider PPI higher quality then MTX, and also one has to consider the efficency.... basically though, i would love to test each one of those amps, i dont know you, and i dont know how they where setup, i highly doubt that an amp that doesnt pull more then 30 amps can dim the lights.
If the graph shows you that the voltage isnt stabilized with a capacitor, your statement about the capacitor stabilizing the voltage is false, i dont always agree with Richard, but he has never been known to be untruthful, and that graph is exactly what would happen with any capacitor, it has been proven by others time and time again
The alt is always 'on' when it is rotating... and, if your car is running, then the alt spins... though it only puts out power as needed, kinda like your water facet is always on, but wont release power until u twist the handle, simple, and when the car is running... something is drawing power from the alt, your battery is always drawing power from the alt if it is spining, your battery will never give power unless it no longer is recieving power from your alt, which would happen if the alt's voltage dropped below the charging voltage of the battery, which will happen if the alt is being taxed over the power it can release.
Power wire goes to the battery first because thats the easiest way to install it... would u like to run it to the alt while keeping in mind to keep the wire away from the engine block, and spining objects, no, it would be a pain, this way, its easy, and painless... the alt is wired directly to the battery anyways, you would be using the same amount of wire either way, why not make it simple and go to the battery?? though one should always upgrade the alt to battery wire to the gauge of wire you are using for your power and ground, and one should upgrade battery to ground wire to that same gauge too.... this is because, power isnt coming form the battery, its coming from the alt... if the car is on that is
And did anyone mention a magazine article?? we pulled a graph that richard used to prove this point at a previous time, i personally am recieving no money from any altenator manufacture, though it would be nice
anything else???

 

cool, i figured it was a sealed box, if you are up to building a ported box you should be able to get about 3dbs louder (theoretically you should be able to get twice as loud on the same power) tell me if you want more information... i can help design a box for you

 

 

if you dont mind fixing your above post it would be great, i am pretty sure it was an accident, but you put your response into my quote making it difficult to read

 

jmax....older amps still use caps in the power supply. Follow the link and see the pic of an older Phillips Sound Labs amplifier that was built by PPI around 1994. They aren't huge but they are there. This is a 300W amp and I've not had any problems with that unit causing any dimming problems in my 89 maxima when I had it. In fact I had that amp and another smaller PSL 200W amp one as well. With no dimming problems... Maybe your example had a PS problem or a leaking cap that cold have caused some problems...

http://canuck.audioguy.net/PhillipsSound.jpg

 

It was a late 80's to early 90's Crutchfield amp built by Precision Power. My wife kilt it about a month ago. And I didn't think it was worth soldering a few resisters back in place, it was over ten years old. So I tossed it in the trash. I agree even cheap amps have some capacitance. But generally speaking not as much or high quality as in premium amps. Isn't this one of the many things that Zapco's are praised for? I never hooked teh amp up in my Max so don't know if it would have caused a similar voltage drop. In fact it hadn't been hooked up since college - '95, '96. Actually, now that I think about it I did hook it up in my Max for about a month and had no dimming. But I have a cap, an alt, and high gauge wiring. My wife's car lacks the cap.

 

just out of curiousity, did you upgrade all 3 of her important cables under the hood?

eric

 

Nah, currently she has a 2 gauge power wire. I haven't upgraded anything else because I never intended to give her more than the Precision Power amp, which used a 25 amp fuse. But I am going to upgrade everything soon for an ARC 1500D-R to power the ten inch Brahma in my basement. Probably place the order tomorrow for the 0 gauge cable. Already have the cap sitting in the drawer next to me.