Why you don't need a capacitor

[ZeusVI]

A) I thought Richard Clark helped invent the cap.

Misconception. Caps were around bfeore he was born, and used as hi pass crossovers when he had diapers on.

B) All amps have caps in them.[/QUOTE]

Yes - for power supply voltage ripple stabilization - and the amp has more than enough to do the job.
Caps are good for a ew microseconds worth of pak/sag stability, but when your B+ voltage drops, so does the cap.

16 or 20 volt caps are used in auto audio, and they do not charge to 16/20 volts, just to line voltage level. Loss in capacitance results, linearly, according to how 'undercharged' the cap is - they never charge fully.

Also, I have seen a true 1/2 Farad capacitor- and they are bigger than the 1 farad offered by audio brands. If you peel the labeling off, you will find a .3-.5 farad cap under the 1 Farad label. So there goes 1/2 to 2/3 o the pow they 'offer' right there. Then figure the prcent charged - 13.5/16 at best you get 84 percent there. So 1/2 advertised power, then only 80 percentof that. Every Fard you buy gives you .4 farads. NO GOOD!!!

[odieoverclock@yahoo.com]

I meant Richard Clark helped invent the Stiffening capacitor as it pertains to use in car audio.

Here is another view of why you need a Stiffening Capacitor, which makes me think Richard Clark is stating "why you don't need a capacitor for SPL systems"

The vast majority of audio/video system installations can benefit from a much easier method of stabilizing voltage than a complete alternator change. This involves installing a power supply capacitor. The power supply capacitor is also know as the "stiffening capacitor."
Technically, a power supply capacitor functions to oppose changes in voltage. When it sees higher voltage, it stores the energy and when it sees lower voltage, it dumps that stored energy in an effort to stabalize voltage levels. The more severe the difference of voltage levels, the more energy dumped out of (or into) the capacitor. More capacitance simply means more storage or longer periods under which the voltage will remain stable. In extreme situations, capacitors can take longer to gather charge than they have until the next call for stabilizing voltage comes along. Capacitors take five times longer to change than they do to bup their effective energy (in a mobile audio voltage stabilizing application). So, in an effort to stablize voltage in typical consumer applications (we are not talking about competitive SPL vehicles here), capacitors provide an alternative to an alternator upgrade in many situations. It is an alternative to the big step of an alternator upgrade because of the nature of the work that the electrical system is asked to do. It is not as if a mobile audio/video system has the same 10 percent duty cycle of a window defroster or A/C blower motor. Instead, the electrical work required to supply a mobile audio/video system is somewhat random in duty cycle. The workload placed on the vehicle depends on the signal content of the sound source being played.
(MECP Advanced Installer Study Guide)

[SCHMITTY]

I think in a nutshell, it's "A cap will help smooth out your voltage, but it won't replace the function of an alternator over any period of time greater than a second or two."

[Kryptonitewhite]

Originally Posted by odieoverclock@yahoo.com

A) I thought Richard Clark helped invent the cap.

B) All amps have caps in them.

who the **** are you and where the **** did you come from? Stop posting and keep reading. I have a feeling you may be knowledgeable someday. not today.

[fosg8freak]

Originally Posted by Kryptonitewhite

who the **** are you and where the **** did you come from? Stop posting and keep reading. I have a feeling you may be knowledgeable someday. not today.

Calm the **** down dude...

[Kryptonitewhite]

Originally Posted by fosg8freak

Calm the **** down dude...

my apologies. I kept my mouth shut with The.End in the beginning, now it's easier to try to snuff out others like me: people who think they know what they're talking about, and don't realize some people may listen to their misguided opinions and make mistakes themselves.

I apologize. Sorry man.

[odieoverclock@yahoo.com]

Originally Posted by Kryptonitewhite

who the **** are you and where the **** did you come from? Stop posting and keep reading. I have a feeling you may be knowledgeable someday. not today.

I am the ******* 15yr Installer day "in a local 12v store not shade tree"/ Live sound Engineer evening. 35yr old male, who has owned speakers ranging from 1/2in to 32in, and power handling from 5w - 8000w. Compeeted IASCA SQ & SPL in the 90's now an avid SQ custom builder. I was around in the days when $ was not the factor for the loudest systems, it came down to who can make a better box. That's who I am. What the hell is your problem. From all the posts that I keep "READING" it seems to me that most people with systems here could benifit from a cap, it would help the system on a budget. I know what the hell I am talking about, and set up stereo systems that you could only imagine. Try 3000+ people wanting bass in a huge venu. When you run out of room in your vehicle try live sound.

[Kryptonitewhite]

Originally Posted by odieoverclock@yahoo.com

I am the ******* 15yr Installer day "in a local 12v store not shade tree"/ Live sound Engineer evening. 35yr old male, who has owned speakers ranging from 1/2in to 32in, and power handling from 5w - 8000w. Compeeted IASCA SQ & SPL in the 90's now an avid SQ custom builder. I was around in the days when $ was not the factor for the loudest systems, it came down to who can make a better box. That's who I am. What the hell is your problem. From all the posts that I keep "READING" it seems to me that most people with systems here could benifit from a cap, it would help the system on a budget. I know what the hell I am talking about, and set up stereo systems that you could only imagine. Try 3000+ people wanting bass in a huge venu. When you run out of room in your vehicle try live sound.

i said I was sorry, but, I don't care if you work at best buy and have installed 1 million systems. reading a few of your comments has made me skeptical, that is all. I also stated that I am the same way... I have ideas that are way out there, and the regulars on this forum know that. I do apologize, I meant no offence. I was wrong.

[odieoverclock@yahoo.com]

Originally Posted by Kryptonitewhite

i said I was sorry, but, I don't care if you work at best buy and have installed 1 million systems. reading a few of your comments has made me skeptical, that is all. I also stated that I am the same way... I have ideas that are way out there, and the regulars on this forum know that. I do apologize, I meant no offence. I was wrong.

Stop insulting me, I would never work for BB, btw BB has not been open for 15yrs

[Krannyman92]

ill be the one to say it. guys...stop getting butthurt over each other. STFU already about it please. we dont want another The.End situation on our hands do we

[johnecon2001]

Originally Posted by odieoverclock@yahoo.com

Stop insulting me, I would never work for BB, btw BB has not been open for 15yrs

They've actually been open for 26 years tough guy.

[Krannyman92]

Originally Posted by johnecon2001

They've actually been open for 26 years tough guy.

how about 43 .

Best Buy - Wikipedia, the free encyclopedia

right side, Founded 1966

edit: your right, 1983 the Best Buy logo started up, i fail. "1983 – Sound of Music’s board of directors approves a new corporate name: Best Buy Co., Inc."

[Fallen]

This whole argument is pointless...

Ugh...
The ESR of the car audio stiffening caps are too high to be of any use. Their energy density compared to AGM batteries is many orders of magnitude lower. They may fix light dimming...but so do AGM batteries. And I don't believe for 1 second that AGMs can't discharge fast enough for good transient response.

But hey, to each their own. I'm gonna stick with my red top lol.

[Kryptonitewhite]

Originally Posted by odieoverclock@yahoo.com

Stop insulting me, I would never work for BB, btw BB has not been open for 15yrs

lol, well as stated in the PM, I like BB way more than the local audio sales...er... tech guys

[Kryptonitewhite]

Originally Posted by Fallen

This whole argument is pointless...

Ugh...
The ESR of the car audio stiffening caps are too high to be of any use. Their energy density compared to AGM batteries is many orders of magnitude lower. They may fix light dimming...but so do AGM batteries. And I don't believe for 1 second that AGMs can't discharge fast enough for good transient response.

But hey, to each their own. I'm gonna stick with my red top lol.

that is why I like this guy

I want my red tops back btw... but, i do miss the digital voltage meter on my cap that got stolen...and the "comfort" that the cap has to have helped just a wee tiny bit... i'm sure it was better to have it than not to have it... but i will never ever buy one again unless i win the lotto..then hell yes, I'd make my own TRUE 100 farad bank, or whatever size would permit for true farads

[ZeusVI]

It's amazing how we think a cap fixes the headlight dimming, etc...So we add it to the amplifier circuit....Get smart and put a 16v cap on the hot right before the headlight relay. Or on the power wire to the main relays. Where they belong.

And stating that a cap will help - the only circumstances that require a cap is when the amp has insufficient capacitance for the power supply. In which case, you need an AMP, not a capacitor.

If you have sag when the amp hits, GET A BATT OR ALT. And dont forget the fat cable. SIMPLE.

Ever have anything in life that was a simple problem, and didnt have a simple fix? Then you complicted it by band-aiding the symptom, not the problem? In car audio, the complicated band-aid is the Power Capacitor. If you PROPERLY design your system, it is not needed. SIMPLE.

[Kryptonitewhite]

Originally Posted by ZeusVI

And dont forget the fat cable.

cant say i agree there..... I get so much hate for running 6 red tops, no HO alt (but intend to do so) and only 4 gauge

**** the fat wire, unless you have enough $$$$ for that too

[FuBaR]

OK all, I guess we all have mixed emotions on the "capacitor" issue. Let me first stay I am just an beginner at this but let me explain my set up first:

1992 Nissan Primera(Infiniti G20 in states) w/ upgrade HO alt and big 3 upgrade to 1/0.
2 Memphis 16 st-1000 watt DClass Sub amps
2 Memphis 15 inch M1 Subs (4ohm DVD)
2 Memphis 16 st-3004 4 channel amps for interior
2 pair JVC 6x9 built into the rear deck - 1st 4 channel
2 pair JVC 6.5 seperate pairs in front staging - 2nd 4 channel amp
1/0 Memphis power and ground wire to Rockford Fosgate fused & unfused distro blocks)
2 Kinetik HC-800 batteries up front wired in series.
2 JVC DVD players built into the dash with a JVC 7 inch motorized flip out on top.
2 Lightning Audio 1 Farad Capacitors - I didn't need them, but no issues with set up either way. I guess I just liked the idea of 'them'. No light dimming before or after installation of caps....that I can remember. No serious voltage change either. well, you guys/girls have a great day. I am off to save the world again today. take care

[ZeusVI]

And that comes from a guy that's never had problems with it once system design is finished. And I run all class a/b amps..And you are recommending a cap here in the dys of class D efficiency...NO, NO, NO!!!

Caps are NOT SIZED ACCURATELY - Car audio branded ones are 50 percent lower value than advertised. Your mega-sized 2 farad cap is less than 1 farad. Then multiply the resulting size by this :
Battery Voltage/caacitor operating voltage.

cap size / 2 *(voltage before cap/Cap rating)
So, once again, 1farad/2 *(13.5/16)
This means .5farad * .84375 which equals .421875 farad for every farad you buy.

Do you even have an idea how to calculate the effect of a capacitor on a voltage sag of 1 volt on a line voltage of 13.5? A full farad is worth about 3/100 of a second at keeping the voltage at 1/2 of the sag. At constant output, it will take close to 3 seconds to recharge fully, AFTER OUTPUT CEASES. It never ceases in audio!! The cap strains current flow as it attemptsto recharge!!! So to get That pitiful 1.0 farad result, you need 2.5 farads of marketed audio brand capacitor. Which issn't enough. You would need no less than 5 farads to even think you did anything, and That costs as much as a battery, which will fix the prblem, not patch it.

But then again, batteries don't come with LED's...
Or an output thats inflated, like an amp thats overrated, sorry that I hated, on your cap thats alwys strainin, capacitance all faded, he 12 volt masturbated, your battery is waiting, up your amperage rating, and stop the sound from fading, e-lec-tric-cal-ly jading got 2 go Im mating.....

[Fallen]

Originally Posted by Kryptonitewhite

cant say i agree there..... I get so much hate for running 6 red tops, no HO alt (but intend to do so) and only 4 gauge

**** the fat wire, unless you have enough $$$$ for that too

Krypto buddy...6 redcaps is overkill with 4 AWG.
Honestly you'd be better off with 2 red tops and a run of 1/0 for positive and negative. The I^2R losses in 4Awg are pretty high when you get into the 500Arms range...I don't see running 6 redcaps being beneficial for any less. Honest to god 1/0 is much better, there will be less voltage dropped across it, and thus less resistive losses.

Lets say you had a 6kW system, that happens to draw 500A of current when it's being played full tilt. The round trip length of your 4awg wire is 50ft. The resistance of copper wire of that guage is 0.2485R/1000ft. So your R*I^2 losses are (0.2485*50/1000)*500^2=
50ft * (0.2485R / 1000ft) * (500A^2) = 3106.25Wrms...as heat, you'll start a fire...


Lets say you had a 6kW system, that happens to draw 500A of current when it's being played full tilt. The round trip length of your 1/0awg wire is 50ft. The resistance of copper wire of that guage is 0.09827R/1000ft. So your R*I^2 losses are (0.09827*50/1000)*500^2=

50ft * (0.09827R / 1000ft) * (500A^2) = 1228.375Wrms as heat.


Anyways there is a reason guys run multiple runs of wire...
Honestly those figures are wrong, because of the series resistance of the wire, the amp will never be able to draw the 500A(the voltage will be sagging like a mofo across the wire).

Either way...I'd run the phat wire BTW NEC specs 4AWG for only 95A of current with 95 degree insulation...(Ie some hot assed wires with only 95A, let along 500...)

Just sayin...

(BTW it's a little more reasonable with lower currents, for my system it's
((0.09827 * 50) / 1000) * (200^2) = 196.54W. Recall that P=IV therefore I'd be dropping 0.986V across the wire, which seems reasonable. With 4awg it would be a 2.5V drop, and 500Wrms of heat.)

[ZeusVI]

Whatever is sufficient. I grounded a punch 150 amp on a coat hanger once and duct-taped it to the rear wall of my truck...and STILL LOST the 'Shippiest car stereo ' award -
first prize was an orion 2150 sx that year..

. I lost to a guy with 8 freeaired pyramid 6x9's off a sparkomatic tape deck Zip-tied to the dash and 2 4-channel roadmaster watt-booster e.q.'s pushing them. I still think it was rigged.

3rd place was taken by the folger coffee can trick, used as a 2x6" alpine bass cannon. But he had a front stage, or else he might have won.

Originally Posted by Kryptonitewhite

cant say i agree there..... I get so much hate for running 6 red tops, no HO alt (but intend to do so) and only 4 gauge

**** the fat wire, unless you have enough $$$$ for that too

[Kryptonitewhite]

Originally Posted by ZeusVI

Or an output thats inflated, like an amp thats overrated, sorry that I hated, on your cap thats alwys strainin, capacitance all faded, he 12 volt masturbated, your battery is waiting, up your amperage rating, and stop the sound from fading, e-lec-tric-cal-ly jading got 2 go Im mating.....

dude, youre the ****! hahahahahahaha

Originally Posted by Fallen

Krypto buddy...6 redcaps is overkill with 4 AWG.
Honestly you'd be better off with 2 red tops and a run of 1/0 for positive and negative. The I^2R losses in 4Awg are pretty high when you get into the 500Arms range...I don't see running 6 redcaps being beneficial for any less. Honest to god 1/0 is much better, there will be less voltage dropped across it, and thus less resistive losses.

Lets say you had a 6kW system, that happens to draw 500A of current when it's being played full tilt. The round trip length of your 4awg wire is 50ft. The resistance of copper wire of that guage is 0.2485R/1000ft. So your R*I^2 losses are (0.2485*50/1000)*500^2=
50ft * (0.2485R / 1000ft) * (500A^2) = 3106.25Wrms...as heat, you'll start a fire...


Lets say you had a 6kW system, that happens to draw 500A of current when it's being played full tilt. The round trip length of your 1/0awg wire is 50ft. The resistance of copper wire of that guage is 0.09827R/1000ft. So your R*I^2 losses are (0.09827*50/1000)*500^2=

50ft * (0.09827R / 1000ft) * (500A^2) = 1228.375Wrms as heat.


Anyways there is a reason guys run multiple runs of wire...
Honestly those figures are wrong, because of the series resistance of the wire, the amp will never be able to draw the 500A(the voltage will be sagging like a mofo across the wire).

Either way...I'd run the phat wire BTW NEC specs 4AWG for only 95A of current with 95 degree insulation...(Ie some hot assed wires with only 95A, let along 500...)

Just sayin...

(BTW it's a little more reasonable with lower currents, for my system it's
((0.09827 * 50) / 1000) * (200^2) = 196.54W. Recall that P=IV therefore I'd be dropping 0.986V across the wire, which seems reasonable. With 4awg it would be a 2.5V drop, and 500Wrms of heat.)

fair enough. next time, wire will be taken more seriousely

Originally Posted by ZeusVI

Whatever is sufficient. I grounded a punch 150 amp on a coat hanger once and duct-taped it to the rear wall of my truck...and STILL LOST the 'Shippiest car stereo ' award -
first prize was an orion 2150 sx that year..

. I lost to a guy with 8 freeaired pyramid 6x9's off a sparkomatic tape deck Zip-tied to the dash and 2 4-channel roadmaster watt-booster e.q.'s pushing them. I still think it was rigged.

3rd place was taken by the folger coffee can trick, used as a 2x6" alpine bass cannon. But he had a front stage, or else he might have won.

wow today has been a fun day!

[blue fury]

[Kryptonitewhite]

Originally Posted by blue fury

um....ya! what the duece, dude?

[ZeusVI]

Wow, only 128 posts,and I finally got quoted...lol.....
Krypto, the smaller wire is fine if you keep it short. But thin and short....My girl likes my long fat cable though...

Seriously, If you can get buss bars or super fat cable to the distro block, a foot of 2awg/4awg won't be audibly different than a foot or so of 0 or 1/0awg.

How far is it from your battery bank to the amplifers?