So how many of you believe that adding a large capacitor between your battery and aftermarket amp is worthwhile and in fact neccessary? I have been searching the internet and most believe when adding an amp to drive a sub that putting in a capacitor is a good thing. However, others disagree. What are your thoughts?
car amplifiers and capacitors.......
- Thread starter mikeinaustin
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Its better to put an inductor in series with the power feed to the amp, and then put a capacitor to ground on the amp side of the inductor. A cap by itself won't be nearly as effective at filtering the ripple off the power. The ripple comes from the alternator rectifier bridge.
the capacitor is like a huge storehouse of electrons. when the amplifier needs a surge of current to supply a musical peak, it has to come from somewhere. regular wiring is not heavy enough to supply the peak, so the voltage will sag, and you will get distortion. some installers put a second battery where the spare tire used to go, and the amplifier right next to it. instead of putting a battery, you can use a capacitor which will do the same thing much more cheaply and safely. you can get great deals for these things, on Amazon. a sub will draw a lot of impulsive power, and a capacitor is perfect to supply it. the capacitor should be right next to the amp, and use heavy guage wire.
Originally Posted By: d00df00d
AFAIK, a capacitor does nothing that better equipment and/or wiring can't do better.
Capacitors are quite useful for driving large woofers that require a large amount of power very quickly and would otherwise drop the voltage across the battery to an unsustainable level.
AFAIK, a capacitor does nothing that better equipment and/or wiring can't do better.
Capacitors are quite useful for driving large woofers that require a large amount of power very quickly and would otherwise drop the voltage across the battery to an unsustainable level.
How big an amp are you thinking about ?
You could always run a heavy dedicated hot wire from the battery (fused of-course). I don't think a large capacitor would help you, you would need a cap measured in farads, not uf, to sooth the b+ line. You would never hear a little distortion in a sub anyway.
My $0.02 Canadian as a retired electronics tech.
You would never drop the voltage across the battery, your starter won't drop the voltage and neither would a sub woofer.
You could always run a heavy dedicated hot wire from the battery (fused of-course). I don't think a large capacitor would help you, you would need a cap measured in farads, not uf, to sooth the b+ line. You would never hear a little distortion in a sub anyway.
My $0.02 Canadian as a retired electronics tech.
You would never drop the voltage across the battery, your starter won't drop the voltage and neither would a sub woofer.
Capacitors are good, quality amps come with a decent amount inside. However, installing an inline capacitor to your amp is not really going to do to much as far as performance. One this for sure is that they will not band-aid or fix a problem. If your alternator is providing say 100amp under load, and your amp is drawing a lot of current under load/lound levels, a capacitor is only going to help with the amount of current available to it. For instance, if your bass is dimming your lights because the amp is robbing current from other circuits in the vehicle, and you add a capacitor to try to correct it you will be disapointed. It will store engery for quick release to your amp, but it still only going to store a certain amount of power. I guess what I am saying is your amplifier is only as good as your charging system. It probably will not hurt your performance, but don't expect anything noticible. You see a HUGE range of pricing on amplifiers that spec the same power output. One big difference in quality and price of an amplifier is the power supply. Look inside a high quality well bit amplifier and you will see heavy coils, a strong capacitor bank, and higher gauge wiring.
My best advice is buy a quality amplifier, match with a subwoofer that is going have the efficiency specs to fit your application. Use quality copper, cheap power and speaker wire are mainly insulation and low copper content because copper is expensive, and a quality install. You shouldn't have any issues. Now start doing things low lowering impedance and you start putting a lot of stress and load on the input stages of you amp and intern generate heat, lose efficiency, and lose reliability.
My best advice is buy a quality amplifier, match with a subwoofer that is going have the efficiency specs to fit your application. Use quality copper, cheap power and speaker wire are mainly insulation and low copper content because copper is expensive, and a quality install. You shouldn't have any issues. Now start doing things low lowering impedance and you start putting a lot of stress and load on the input stages of you amp and intern generate heat, lose efficiency, and lose reliability.
Originally Posted By: Papa Bear
How big an amp are you thinking about ?
You could always run a heavy dedicated hot wire from the battery (fused of-course). I don't think a large capacitor would help you, you would need a cap measured in farads, not uf, to sooth the b+ line. You would never hear a little distortion in a sub anyway.
My $0.02 Canadian as a retired electronics tech.
You would never drop the voltage across the battery, your starter won't drop the voltage and neither would a sub woofer.
Fifty years ago a sagging power supply could influence the output waveform... but with modern operational amplifiers including adequate feedback these will be fully compensated for by the amp. Once you reach the absolute output limit:
1. The output power will clip
2. you will go deaf
3. Your screeching speakers will keep you from hearing emergency sirens in traffic, and you will be killed anyway!
Yes, the caps would be small compared to the battery power using heavy wire - but audio stores find lots of reasons to sell people stuff!
And they hope most customers do not know a lot about electronics except for a few catch phrases.
BTW all good amplifier designs already have capacitors in them.
I would do the following: Put on something will lots of bass, tell the audio shop to show you the waveforms and see if you ever reach the clipping threshhold. If they do not know what clipping is........
RUN!!!
How big an amp are you thinking about ?
You could always run a heavy dedicated hot wire from the battery (fused of-course). I don't think a large capacitor would help you, you would need a cap measured in farads, not uf, to sooth the b+ line. You would never hear a little distortion in a sub anyway.
My $0.02 Canadian as a retired electronics tech.
You would never drop the voltage across the battery, your starter won't drop the voltage and neither would a sub woofer.
Fifty years ago a sagging power supply could influence the output waveform... but with modern operational amplifiers including adequate feedback these will be fully compensated for by the amp. Once you reach the absolute output limit:
1. The output power will clip
2. you will go deaf
3. Your screeching speakers will keep you from hearing emergency sirens in traffic, and you will be killed anyway!
Yes, the caps would be small compared to the battery power using heavy wire - but audio stores find lots of reasons to sell people stuff!
And they hope most customers do not know a lot about electronics except for a few catch phrases.
BTW all good amplifier designs already have capacitors in them.
I would do the following: Put on something will lots of bass, tell the audio shop to show you the waveforms and see if you ever reach the clipping threshhold. If they do not know what clipping is........
RUN!!!
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I think a better investment for any mega-amp installation is rubber coated fasteners. The buzzing of body parts just doesn't fit into my idea of "quality sound".
Patman
Staff member
I have a small 500k farad capacitor that I use for my Corvette's stereo system, as I have a couple of Fosgate amps, the biggest of which is a P500 which is currently putting out almost 700 watts RMS. I use that for the single 12 inch sub. With my system cranked up, when the bass kicks in my lights barely flicker at all. With previous systems similar to this in other cars I've owned, without a cap, I would find the headlights would dim badly every time the bass hit. So I definitely think running a cap on a high power system is a good idea!!
Here are a couple of shots of my system:
Here are a couple of shots of my system:
It's a 500k uf capacitor.
A 500k farad capacitor wouldn't fit in my Chevy Uplander..
Mike in Austin must have gone on vacation, he never did say how much power his amp was.
A 500k farad capacitor wouldn't fit in my Chevy Uplander..
Mike in Austin must have gone on vacation, he never did say how much power his amp was.
Patman
Staff member
Originally Posted By: Papa Bear
It's a 500k uf capacitor.
A 500k farad capacitor wouldn't fit in my Chevy Uplander..
Oops, I don't know my electronics numbers that well, I just thought that's what it said on the side of it there.
It's a 500k uf capacitor.
A 500k farad capacitor wouldn't fit in my Chevy Uplander..
Oops, I don't know my electronics numbers that well, I just thought that's what it said on the side of it there.
Capacitors in the 500k farad and above size are called "flux capacitors" and are used exclusively in Deloreans, mostly just for time travel! Storing 1.21 gigawatts is no easy matter.
700 Watts in a Corvette?? Are you the one I see in traffic, oblivious to the ambulance sirens behind you?? LOL
I like the rubber coated fasteners idea, at least the rattling vibrations sounds will be reduced for the innocent ears around you!
700 Watts in a Corvette?? Are you the one I see in traffic, oblivious to the ambulance sirens behind you?? LOL
I like the rubber coated fasteners idea, at least the rattling vibrations sounds will be reduced for the innocent ears around you!
Patman, I'm wrestling with a bad head cold today and my thinking is fuzzy but I believe that a 500k f capacitor would be 1,000,000 times larger in capacity than your 500k uF.
Patman
Staff member
Originally Posted By: fsskier
700 Watts in a Corvette?? Are you the one I see in traffic, oblivious to the ambulance sirens behind you?? LOL
Actually it's approximately 900 watts RMS, as there are two amplifiers in my system, one for the sub and one for the components set up front. I do like to listen to it loud a lot but surprisingly it doesn't sound that loud outside of the vehicle when the windows are up. I don't listen to "boomy bass" type of music, I prefer listening to good music that has nice tight bass to it, not the goofy "speaker testing" kind of music that you often hear blasting from other cars at stoplights. I would have preferred to have gone with two ten inch subs for tighter bass, but it was easier to just do a single 12, using the center storage bin as the enclosure. I find the single 12 doesn't quite have the nice tight bass I prefer, but overall the system has much nicer sound than the original factory stereo, and because a friend did all the labor for me for free, the entire system cost me under $1500 (I collected the parts over a few months, buying everything new and simply waiting for good sales)
700 Watts in a Corvette?? Are you the one I see in traffic, oblivious to the ambulance sirens behind you?? LOL
Actually it's approximately 900 watts RMS, as there are two amplifiers in my system, one for the sub and one for the components set up front. I do like to listen to it loud a lot but surprisingly it doesn't sound that loud outside of the vehicle when the windows are up. I don't listen to "boomy bass" type of music, I prefer listening to good music that has nice tight bass to it, not the goofy "speaker testing" kind of music that you often hear blasting from other cars at stoplights. I would have preferred to have gone with two ten inch subs for tighter bass, but it was easier to just do a single 12, using the center storage bin as the enclosure. I find the single 12 doesn't quite have the nice tight bass I prefer, but overall the system has much nicer sound than the original factory stereo, and because a friend did all the labor for me for free, the entire system cost me under $1500 (I collected the parts over a few months, buying everything new and simply waiting for good sales)
I don't fiddle with car audio much, and I'm probably splitting hairs that needn't be split, but I'd have two concerns:
1) Transient response might slow down a bit, the more stuff you stick inline. Listening to good music with tight bass might suffer some; although a car - especially a Corvette - is far from an audiophile listening environment.
2) The phase nonlinearity of sticking a cap on the sub channel only, leaving the high pass audio alone. A cap is gonna shift your current by 90 degrees, no?
1) Transient response might slow down a bit, the more stuff you stick inline. Listening to good music with tight bass might suffer some; although a car - especially a Corvette - is far from an audiophile listening environment.
2) The phase nonlinearity of sticking a cap on the sub channel only, leaving the high pass audio alone. A cap is gonna shift your current by 90 degrees, no?
Patman
Staff member
Originally Posted By: uc50ic4more
2) The phase nonlinearity of sticking a cap on the sub channel only, leaving the high pass audio alone. A cap is gonna shift your current by 90 degrees, no?
I am pretty sure that the cap in my car is wired in for both of the amps, not just the one that drives the subs.
2) The phase nonlinearity of sticking a cap on the sub channel only, leaving the high pass audio alone. A cap is gonna shift your current by 90 degrees, no?
I am pretty sure that the cap in my car is wired in for both of the amps, not just the one that drives the subs.
OK, except for those of you that own a Delorean....
Patman's capacitor is likely a .5 farad capacitor, or 500K uf, either is an accurate expression of the same number.
500k uf means the same as "500,000 one/millionths" of a farad.
The flux capacitor - used in Delorean's - can store an entire lightning bolt inside of it but is very dangerous if you drop a wrench across the terminals!!
Patman's capacitor is likely a .5 farad capacitor, or 500K uf, either is an accurate expression of the same number.
500k uf means the same as "500,000 one/millionths" of a farad.
The flux capacitor - used in Delorean's - can store an entire lightning bolt inside of it but is very dangerous if you drop a wrench across the terminals!!
Originally Posted By: uc50ic4more
I don't fiddle with car audio much, and I'm probably splitting hairs that needn't be split, but I'd have two concerns:
1) Transient response might slow down a bit, the more stuff you stick inline. Listening to good music with tight bass might suffer some; although a car - especially a Corvette - is far from an audiophile listening environment.
2) The phase nonlinearity of sticking a cap on the sub channel only, leaving the high pass audio alone. A cap is gonna shift your current by 90 degrees, no?
It sounds like he is putting the cap on the 12V DC power supply side of the amp, not the audio side. It's done to make up for inadequate wiring or other power supply problems and has no direct effect on phase linearity.
I don't fiddle with car audio much, and I'm probably splitting hairs that needn't be split, but I'd have two concerns:
1) Transient response might slow down a bit, the more stuff you stick inline. Listening to good music with tight bass might suffer some; although a car - especially a Corvette - is far from an audiophile listening environment.
2) The phase nonlinearity of sticking a cap on the sub channel only, leaving the high pass audio alone. A cap is gonna shift your current by 90 degrees, no?
It sounds like he is putting the cap on the 12V DC power supply side of the amp, not the audio side. It's done to make up for inadequate wiring or other power supply problems and has no direct effect on phase linearity.
I'm quite sure a high power 12 volt amp would be powered by an SMPS (switch mode power supply). A good SMPS will compensate for fluctuating input voltage.
Lets say the voltage of the SMPS is 80 volts to power the audio output stage. It would maintain that 80 volts whether the battery supply is 12 volts, 14 volts. 11 volts etc... you get the idea.
That's my fuzzy headed $0.02 today.
Lets say the voltage of the SMPS is 80 volts to power the audio output stage. It would maintain that 80 volts whether the battery supply is 12 volts, 14 volts. 11 volts etc... you get the idea.
That's my fuzzy headed $0.02 today.
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