Adding capacitor

[built]

hi,

i have search and google but cannot seems to find any answer
to why adding 2, 3 or 4 capacitors of 33,000 uF/16Vdc in parallel
just before the head unit changes the sounding?

i tried. first, one capaitor then another one install parallel to the
first one. the sounding has become "thicker" or "harder" and the
bass has become tighter. will soon try out 3 capacitors.

appreciate very much. thanks.

[thermonuclear]

Is the head unit running any speakers or are they all being powered by amplifiers. I am interested in this theory as well. I would think it would only have an affect on a headunit that is powering the speakers not on one with outboard amplifier(s).

[built]

nope, the speakers and sub are powered by amplifiers.
hu -> amplifiers (one for components and one for subwoofer) -> passive crossovers -> speakers

those capacitors are cans aluminium electrolytic, helix cap33
or BHP Aerovox. i am using 16Vdc to try out. will later change
them to higher rating.

[junglejuice]

Quick question before the caps were fitted did the lights on the head unit dim or flicker at all when the bass hits? If so now that the caps are fitted does it still do it?

Having the caps on the head unit is like fitting one to the amp it will help to maintain the voltage to the head unit which in turn will help to maintain signal strength.....

[built]

no, no diming of lights or anything before caps are installed.
it was purely by trial/chance.

[IowaDave]

I have heard similar results from upgrading the Big 3. (Alt - to chassis) (batt - to chassis) (batt+ to alt +). limits dimming of of stock equipment during large amp hits. never tried a cap on my HU however.....interesting idea.

[jnb]

If you have several, try fitting just one before your H/U and the rest before your amps.

[built]

those used at the hu are rather small valued capacitors.

i have one each, for my component and sub amp. they are 1F.
i would probably will replace them with a set of 5x0.2F each later.

[troystg]

Caps at the head unit compensate for the "usual" crappy factory wiring and give the HU am immediate local source of pwr.

They work well with dead heads and powered units.

Only 2 caps are required. Constant +12V and switched +12V. A cap between Constant and switched is wasted.

Caps on the HU should be polarized electrolytic ~25 volt and 200-2000uF. A good rule of thump is the HU staying on a second or two longer after the ignition is turned off. Any more than that and you risk popping fuses with the charging surge to the cap when the ignition is turned on.


Caps on amplifiers should be polarized electrolytic ~25 volt and > 1Fd.