improving amplifier transients by large capacitor banks

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i have just seen some latest focal car amps and some other high end stuff which is meaner on power supply regulation capacirtos mostly after step up stage in the car amp its around 6500uf total for an amp rated 150 w per channelx2 now i was comparing it with vintage sony home amps with dual capacitor banks...12000UFx2 for the power module and 5500uFx2 for the amplificatier small signal......for sony TNA 330 ES vintage amplifer which is rated mere 110 W per channel. The focal 2.150 car amp is no cheaper both are class A/B but focal lacks dynamics even on reference series car components.....just a hint that the the capacitor bank in the vintage sony were lined up on the PCE then dual held together with plated coated with red velved for vibration control and then even individual cpacitor is stripped across is mid with an iron strip secured with a screw to eliminate vibtaion... the chasis is mad of pure aluminium must be 10 kg alone and the transformers are toriod in sheileded heavy cast metal....whereas the focal car amps have open step up transformers wotout shielding......>>>Sony ta-n330es image by McPics on Photobucket
and
Sony ta-n330es image by McPics on Photobucket
and
Sony ta-n330es image by McPics on Photobucket


just wanted to check would there be any benefit of addiing 12000uf capacitor bank X2 on both rails insteasd of 3300 dual bank...on my Focal 2.150.
 
Car power amps use switching power supplies at 25kHz up, and mains-powered amps have 100/120Hz ripple frequency- a huge difference! Car amps don't need as big filter capacitors.
Instead, I find adding capacitance to the 12VDC feed to the (car) power amp helps the most. I use 100,000-250,000uF with thick wiring. I would try that first.
 
400W/12V=33.33333A

1mm squared cable is enough for 10amps, car has usualy 6-idk mm cables

battery gives out over 70 amps

people put capacitators at inputs so the bass gets food, and its not necesary unless you hear a cliping in the bass

other thing is the switching transformer has to try harder when it gets 10V instead of 12
but again, voltage drop is when the amp demands high power, that is the bass usualy(and Ramstein:))

so the cap, unless you hear clipping(soft clipping i guess), shud give you a little less heat in your amp, but that little is rly little
 
I have found that the bass performance of an amplifier is not just a function of the caps on the power rails. I built two Class AB amps, same output stage, same voltage amplification stage, same power supply, same wiring and same speaker with the same source. One had clearly better bass dynamic. The difference was minor, it was a standard LTP input on the one amp and a CFP LTP input on the other. The improved accuracy and local gain boost of the CFP resulted in less distortion on transients and hence better bass. It did also improve the PSRR so I can't completely separate out the effect of adding more capacitance, but I think there's more to transient performance than caps.
 
A car battery cold cranking current can exceed 1000 amps. The capacitors at the amp 12V input aids in regulating the 12V supply from being modulated by the amplifier and the use of long leads from the battery to the amplifier. Because the leads has resistance there will be a volt-drop across each lead when there is current drawn and the larger the capacitor the less modulation would occur since the capacitor is an instant source of energy.

Capacitors cannot replace thick wires but can only help providing the instant energy when needed. And yes it will help in cleaning up the bass performance.

Nico
 
A car battery is not a really good capacitor

A car battery is not a really good capacitor, it has ESL and dynamic ESR so it is a "mushy" voltage source. If you scope across the battery, you will see: alternator ripple, ignition+injectors+fuel pump noise- all of which can contribute to lack of detail and hazy sound.

The cold-cranking test loads the battery down to 7.2V. Most batteries are about 525CCA but 1000amps= 4.8mohm internal resistance.
15 feet of 10AWG wire is 15mohm, 8AWG is 9mohm.
A 1 farad cap ESR is <2mohm and 2 farad <3mohm. So the cap can definitely help.

Other suggestions to troubleshoot your lack of detail and punch:
Put the Sony amp w/extension cord in your trunk and take a listen.
Change the grounding of your system, as that can have a big effect on car audio quality.
 
1'st car batery cant give over 100A without considrable voltage drop(thats without the wires), and thats 1.1kW while a car amp uses far less

2'nd ripple, pump noise and all dont matter if you have a good regulated power supply, as most are

3'rd Maxwell Technologies - Products - Ultracapacitor - 16 Volt Small Modules - General Purpose Modules
this is 350F/16V, its expencive and new, large one might be 1000F, but i doubt some1 woud use it for starting cars

all in all 1F at the input of the amp and 6mm2 wires is too much
 
In car amps as was already posted you have a switching power supply which is a much higher frequency than the 120 Hz ripple you see off the bridge on a home system. As a result you need much less capacitance to smooth the ripple. Even in a home system the value of large capacitance in a class AB amp is quite small, to the point of being trivial. All you are doing is smoothing the ripple by a fraction of a volt, so you have a fraction of a volt more available before clipping. The article at the link below has more detail.

Increasing Transformer and Capacitor Size
 
"but i doubt some1 woud use it for starting cars"

Batteryless, Environmentally Friendly Car/Truck

For several weeks Larry Schlussler at Sun Frost has been driving his 1982 Ford truck without a starting battery. The battery was removed and replaced by a large capacitor. The 150 farad capacitor is about 1000 times larger than the large capacitor commonly encountered in devices. The energy storage device is capable of storing enough energy to start a very large truck engine. What is needed to start an engine is actually not a large amount of energy but a short burst of power. A capacitor can supply an even larger burst of power than a starting battery. An additional advantage of a capacitor as a starting device is that its output is not affected as much as a starting battery’s during cold weather. The capacitor is about the same size as a starting battery.

*************************************

The 1000F capacitor I mentioned was used for starting tractor-trailer rigs (semi).

provides up to 3000 amps of instant cranking power for any fleet
application, heavy equipment and military vehicles.


Delivers up to 3000 amps of cranking power at 12 volts

Capacitor Powered

30 second charge provides full cranking power

No lead/acid batteries to maintain or replace

Never needs to be plugged into AC power
 
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i have just seen some latest focal car amps and some other high end stuff which is meaner on power supply regulation capacirtos mostly after step up stage in the car amp its around 6500uf total for an amp rated 150 w per channelx2 now i was comparing it with vintage sony home amps with dual capacitor banks...12000UFx2 for the power module and 5500uFx2 for the amplificatier small signal......for sony TNA 330 ES vintage amplifer which is rated mere 110 W per channel. The focal 2.150 car amp is no cheaper both are class A/B but focal lacks dynamics even on reference series car components.....just a hint that the the capacitor bank in the vintage sony were lined up on the PCE then dual held together with plated coated with red velved for vibration control and then even individual cpacitor is stripped across is mid with an iron strip secured with a screw to eliminate vibtaion... the chasis is mad of pure aluminium must be 10 kg alone and the transformers are toriod in sheileded heavy cast metal....whereas the focal car amps have open step up transformers wotout shielding......>>>Sony ta-n330es image by McPics on Photobucket
and
Sony ta-n330es image by McPics on Photobucket
and
Sony ta-n330es image by McPics on Photobucket


just wanted to check would there be any benefit of addiing 12000uf capacitor bank X2 on both rails insteasd of 3300 dual bank...on my Focal 2.150.


Some reader may be misled I think , the author of this post as I understand compares his Sony home amp capacitor bank supply to his car audio amp capacitor bank supply. whilst both are capacitors the Sony is pushing and pulling partial DC from a bridge rectifier originating from a AC supply using capacitors to try to make DC.

The rule of thumb with AC derived power supplies so as not to break rectifiers is 1000 uf for every amp of current that the amplifier under load will deliver. for instance 10,000 uf per rail enables 5 amps of current each rail/ each channel.

If you try and put 1 farad of capacitance through a AC derived PSU either stand back whilst the rectifier evaporates, or properly design for that capacitance- just quietly thats a big bridge rectifier. Switch Mode PSU's cleverly change the frequency of AC so the need of big capacitors filling up and and being drawn from is nearly removed. There has been trend in recent times to use SMPS, and a few hours studying them is well worth while.They are complex, and bring together many ideas how DC can be derived.

Now where the two technologies car and home hi fi can have a romantic dinner together is to stop using ridiculous amounts of capacitance and instead use a transistor arranged as an emitter follower, and place capacitance from base to ground, like magic the transistors HFE characteristic will multiply the capacitance value. Not only that but bandwidth improves. See opamp - opamp construction as shown here a op amp psu greatly benefits from an emitter follower.

Hope this helps / Chris
 
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