do I need a cap for my amps?? | Ford Explorer Forums - Serious Explorations

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do I need a cap for my amps??

October 21, 2003
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hey guys I have 2 amps in my ex I have a 400 watt and I think a 150 watt. I also have the 130 amp alternator I dont have any light dimming problems or anything but I was curious should I get a a cap for my system? What benefits do they offer? and what exactly do they do?


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Yes you do.

Everone with an amp can benefit from a capacitor.

basically when your amp hits hard, like at high volume with a big bass hit, it pulls all the current it can from your electrical system. With a cap the current it needs is already stored up, so it doesnt have a hard time getting the power it needs.
So the answer is yes you could use a cap, but it is more important to first make sure all your wiring is up to par....your system wiring is more important than a cap, the cap should be one of the last things you do.
If you already have top notch wiring then the cap may be your next step.

I am guessing with your system (sounds like 2 amps, about 600 watts) you will need a 1/2 farad cap, should be sufficient.........

Im pretty sure my wiring is all good Its a rockford fosgate dual amp wiring kit and since my second amp powers my door speakers I did run all new wires for the doors. I will start looking around for a good priced cap. do you know of any good places to start looking?

in my opinion, no.

If your lights arent dimming when the bass hits then i would say no you do not need one at this point. I dont have a cap for mine and its fine at lower volumes if i crank it up then the battery meter bounces with the bass and my lights dim but i dont have it cranked up at maximum volume enough to justify buying a cap.

Instead of buying a crapacitor upgrade your battery first, and your wiring (the big 3).

Its not just the wiring to the sub and to the amp that are important your chassis ground is one of the most important upgrades you can do. Also make sure your battery is newer and getting a battery that is a little stronger then you common stuff will be even more of a benefit for you. Cap should be your last RESOLVE. If anything upgrade your alternator first it will be up the electrical like you wouldn't believe....

But to reitterate....chassis ground very important....

i already have a new high output alternator and my battery is an optima yellow top

i have a couple of mobil spec caps for sale that i'll let go for $75 shipped. the are as nice as ANY 1 farad cap and far nicer than many. Let me know if your interested.


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If it were me, id buy the one Expo is selling. In general a capacitor is a capacitor. Theres really nothing one can do to bulld a better capacitor, except for maybe an led readout and better terminals. In the end its still a big cylinder, filled with electrolyte.

and of all the caps i've seen this one has the nicest terminals too. i wish i had a close up of them.

dam man..

took the truck cruising over the weekend with some of my street buddies with lightnings/is300's and all that crap. so I busted the system pretty normal with all my lights on... right behind my friends truck, and I can see my headlights and gauges going in and out slowly... I just cussed out loud- thought my system didn't eat that much power, but eh, looks like i'll be getting one sooner than i expected, since i was only listening to it on like 40/60.

Originally posted by explorermike94
i already have a new high output alternator and my battery is an optima yellow top

wow, then you really dont need a cap, unless you just like the way they look?

And draft, if your lights dim and such with just a rockford 851S, I'd check out the battery and the alternator, cuz thats not exactly a huge drawing amp. Try (if you haven't yet) either a new battery, or a HO alternator. And if you hadn't yet, upgrade the batt ground wire, alternator power wire, and engine ground wire.

Yeah, well, I didn't expect any dimming at all really either. I mean, it was nothing drastic, just noticeable to my eyes during the night, which in some cases if a little tired.. doesn't always pick up the small things like that.

Not that they draw alot of power... but I did have those gauges running, all sylvania upgraded front bulbs, low fogs, upgraded tail bulbs, and of course the system, plus the box was pounding like a ****... I tried one of Jay-Z's new songs on it, and christ, I play it any louder than 25 or 30 (out of 60), the pounding just overdoes the music.. depends on the song I guess. Thinking of readjusting my amp settings anyways in these next few days, sounds like some of the gains got thrown off.

I want a red top soon anyways, so I'll probably just do that. You'd be surpised what I can pull out of that amp... bleh, who knows.