Looking into to getting a cap before I upgrade my alternator.

http://cgi.ebay.ca/ws/eBayISAP...50547

http://cgi.ebay.ca/ws/eBayISAP...&rd=1

whats the difference in them? one is 1.1 farad and the other is 1.2, what does this mean? I really dont get caps. How are they installed

 

I think it's 1000 watts per farad of capacitance, so you could push another 100W with the bigger one.
The cap will charge and act like a small battery so when the amp requires more voltage (when the bass hits) you won't put such a drain on the battery. It also could filter out some voltage spikes - since the cap would absorb the spike and the amp wouldn't see it. So you'd lose the thump of the amp turning on.
You hook them up in parallel with the battery and amplifier. Take your battery power to the + on the cap, and take the amplifier power to that same + on the cap.
Then ground the cap (-) to the chassis and ground the amp to the (-) terminal on the cap.

 

Look into upgrading your grounds first. I have seen enough test that show that caps are garbage. I wouldn't buy one unless you have nothing better to spend your money on. I saw a test where a cap negatively impacted performance though so be careful.

 

how do you test performance of a passive electrical component?

does that mean all these caps i have to put on my circuits at work to keep the power clean are garbage?

 

No... Basically the arguement is that when your bass hits and discharges the cap, if the bass keeps hammering that the system will be unable to recharge the cap due to the high demands and hence the cap becomes a hinderance rather than an aid.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jagan'92 &raquo;</TD></TR><TR><TD CLASS="quote">I think it's 1000 watts per farad of capacitance, so you could push another 100W with the bigger one.
The cap will charge and act like a small battery so when the amp requires more voltage (when the bass hits) you won't put such a drain on the battery. It also could filter out some voltage spikes - since the cap would absorb the spike and the amp wouldn't see it. So you'd lose the thump of the amp turning on.
You hook them up in parallel with the battery and amplifier. Take your battery power to the + on the cap, and take the amplifier power to that same + on the cap.
Then ground the cap (-) to the chassis and ground the amp to the (-) terminal on the cap.</TD></TR></TABLE>

You also have to run a remote wire from your head unit to the cap so that when you turn on the head unit, he cap will turn on too.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by a98tegLS &raquo;</TD></TR><TR><TD CLASS="quote">

You also have to run a remote wire from your head unit to the cap so that when you turn on the head unit, he cap will turn on too.</TD></TR></TABLE>

WTF!

The cap does not get turned on and off.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vteg &raquo;</TD></TR><TR><TD CLASS="quote">

WTF!

The cap does not get turned on and off.</TD></TR></TABLE>
he's probably thinking of those caps that have the electronic display on the top of them.

 

:shakes head aimlessly:


Modified by nsxxtreme at 9:51 PM 11/10/2003

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by brads94accord &raquo;</TD></TR><TR><TD CLASS="quote">
he's probably thinking of those caps that have the electronic display on the top of them.</TD></TR></TABLE>

Yes I am, like BOTH of the options this guy is looking at.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1BlackHatch &raquo;</TD></TR><TR><TD CLASS="quote">Look into upgrading your grounds first. I have seen enough test that show that caps are garbage. I wouldn't buy one unless you have nothing better to spend your money on. I saw a test where a cap negatively impacted performance though so be careful.</TD></TR></TABLE>

 

I only need a cap when my head gets cold.

I use a rule of 500watts (RMS) to a farad of capacitance though. The larger would probably be better. I'm sure anyone can find a test that will negate the benefits of anything. These for the most part help a stereo system. Especially if your headlights dim when the bass hits...

 

I don't know ab out anyone else but my cap holds a charge for atleast 20 seconds, my cap is able to run my entire system (for a small amount of time). Unless you are playing a pitch, considering you have the right watt:Farad ratio, you won't run into many problems with it hindering your system. I bought a cap noticed a difference in how tight and crisp the bass sounds, (because my amp had all the power it needed), then upgraded my grounds and saw less of a dip on the digital display on the cap, both helped grounds are 10 times cheaper to upgrade.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Torridcivic &raquo;</TD></TR><TR><TD CLASS="quote">. I bought a cap noticed a difference in how tight and crisp the bass sounds, </TD></TR></TABLE>

Is it real, or psychoacoustics

There are instrumented tests that have verified that cap use has very limited effects on voltage and sq.

There are people that sell blocks of wood for 5000 that they claim will make your speakers sound better also.

 

no, my power used to be drawn just from a normal battery and the stock alt, no upgraded grounds. when ever I would turn the bass up with the headlights on the bass would be shakey and weak, especialy in the first millisecond. I added the cap and there was no sloppyness, the bass was tight.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vteg &raquo;</TD></TR><TR><TD CLASS="quote">

Is it real, or psychoacoustics

There are instrumented tests that have verified that cap use has very limited effects on voltage and sq.

There are people that sell blocks of wood for 5000 that they claim will make your speakers sound better also. </TD></TR></TABLE>

Come on guys what the hell is this stuff. Those "tests" are for 20 Farad capacitors that have such a high ESR that they act like batteries instead of a cap. The same thing is now used on computer motherboards instead of the lithium memory batteries. Now they use a 1 farad 5v cap with a really high ESR. I=C*dv/dt with some simple math you should be able to figure out the kind of current a capacitor can deliver and for how long. 20 sec is way to long for any thing useful.


An alternator has to use a voltage regulator to control the chargeing levels. Now this device has to make changes to compensate for changes in the load. This takes time. These delays are what the capacitor fixes. In can charge and discharge much faster than the alternator or battery. You would not be able to see these changes with normal equipment. Think about it a light bulb swithes off and on 60 times per second but it appears constant. With an oscilliscope you would easily be able to see this. Now an amplifier sweeps between 20 to 20khz so these changes would be to fast for most multimeters to pick up. You would need a computer or oscilliscope that is able to datalog the data. Then you would need to compare the input waveforms to the output waveforms to pick up any transient changes.

Think of it kind of like a water tower that holds water. Now for visual purposes think of a water hose put in the top to fill the water tower. Obviously this water hose is to small to feed an entire city with water. But if the tower was already filled and everyone turned their water on for a brief period of time, they would notice no changes in the amount of water pouring from there faucet. Now if everyone was to leave their water on until the tower drained then they would notice a huge drop in the amount of water pouring from their faucet. Obviously the continous water flow that this sytem would be able to supply would depend on how much water the water hose could supply. But as long as you only used you water tower reserve for brief periods of time you would be fine. The bad part about this analogy is everyone is probably wondering why not use a bigger hose. Think of the hose supplying the water in the top being turned on and off when needed. It takes time to turn on and off and the water tower would still have a use. But the continous water supply would increase. So caps have a purpose and so do larger alternators. Both should be used wisely.

I will be biting my tongue from now on



Modified by nsxxtreme at 9:10 PM 11/12/2003

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxxtreme &raquo;</TD></TR><TR><TD CLASS="quote">

I will be biting my tongue from now on

Modified by nsxxtreme at 9:10 PM 11/12/2003</TD></TR></TABLE>

Aww. We don't want that

I don't argue that caps have a place in car audio. Just not the place that most people want to use them for. They are not a fix for dimming lights For the occasional current/voltage sag they are great. But definately not a fix for a guy that chooses to mate a 2kw amp to a 90 amp alternator. I have used caps before. I thought they made very little difference, and was not worth the money.

Caps can be an asset if used properly. But YMMV.

BTW, The water tower is a very good analogy.

 

http://www.diyaudio.com/forums....html

 

I cant really see what he is using for his step intervals but a 20 hz wave has a period of 1/20. If your step is 1 sec you will see nothing. The cap effects transient responses. It is used to improve the transient response of your output. Although I will agree with him that that current 20 Farad caps are worthless. Now if you put 20 1 Farad caps together that would be a vary nice capacitor bank with a very low ESR. But would take up a lot of space a be very costly.




Modified by nsxxtreme at 2:14 PM 11/13/2003

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1BlackHatch &raquo;</TD></TR><TR><TD CLASS="quote"> http://www.diyaudio.com/forums....html </TD></TR></TABLE>

Someone from the RC forum was looking for that thread recently. I guess RC cleaned the archives.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1BlackHatch &raquo;</TD></TR><TR><TD CLASS="quote"> http://www.diyaudio.com/forums....html </TD></TR></TABLE>

Thanks for that link. It was very informative.

 

what will the result be like if i got .5farad cap on my 450w amp?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by youngwon22 &raquo;</TD></TR><TR><TD CLASS="quote">what will the result be like if i got .5farad cap on my 450w amp?</TD></TR></TABLE>

With 450 watts, you should not need one. Try one if you want to.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1BlackHatch &raquo;</TD></TR><TR><TD CLASS="quote"> http://www.diyaudio.com/forums....html </TD></TR></TABLE>


THIS WAS AWESOME!!!!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Torridcivic &raquo;</TD></TR><TR><TD CLASS="quote">


THIS WAS AWESOME!!!!!!</TD></TR></TABLE>

The version on RC's forum was like 15 pages or so. I read it over a week or so