The AUSubaru.com.au Forums

hey guys,

just after some background info here.

stereo rundown
-alpine 1000wrms monoblock running 13inch focal sub
-alpine 4x125wrms 4 channel running hertz 6.5 inch splits and focal 6.5inch splits.

both of these amp are under rated and throw abit more power than that

question is, to help minimise the strain on my battery and alternator will a capacitor be beneficial? I heard for every 1000rms you run you should use a 1farad cap? Is this correct?

It does make my headlights and interior lights dim quite badly when its cranked.

Just wondering if theyre all theyre cracked up to be or whether i should just upgrade to a bigger battery?

thanks

alex

I think capacitors are a little over rated.

They wont reduce the strain on your battery as they only store instantaneous energy, but because they smooth out power fluctuations, it might reduce the flickering of the headlights

If your sub amp is 1000Wrms, assume that it will draw 2000W from the cars electrical system (type A/B amplifiers are generally 50% efficient)
That is quite an amp

2kw at 13.8v is 144amps, which is the way too much current for a car electrical system to supply, so are you sure its a rms rating on your amplifer?

What is the rating of the fuse in the amplifier?

Suparoo wrote:I think capacitors are a little over rated.

They wont reduce the strain on your battery as they only store instantaneous energy, but because they smooth out power fluctuations, it might reduce the flickering of the headlights

If your sub amp is 1000Wrms, assume that it will draw 2000W from the cars electrical system (type A/B amplifiers are generally 50% efficient)
That is quite an amp

2kw at 13.8v is 144amps, which is the way too much current for a car electrical system to supply, so are you sure its a rms rating on your amplifer?

What is the rating of the fuse in the amplifier?

the amp has 4x25amp fuses in it. And yes im 100% sure its 1000wrms. Its the second biggest amp alpine do haha.

alex

mind you i have the gain allll the way down.

Ok,... WOW! That is quite an amp.

Even so, i doubt that you will running it at 1000w for any amount of time, otherwise you will need a major alternator upgrade.

Why do you need such a powerful amp? Are you competing in audio competitions?

I had a 4x80w in my last car and i thought that was plenty loud enough

As i said in my previous post, the capacitor will absorb momentary spikes in current (like a loud drum beat) but wont make any difference to actual current required/consumed.

Upgrading to a bigger battery will probably help though.

nah not competing..just love my sound ..some say too much.

but yeh i bought it for the future when i upgrade to a bigger sub.

i did previously have the rear two channels of my 4channel bridged to it, getting just over 350rms(seriously underpowering it), but with the bigger amp it really does blow ya socks off.

Might invest in a new battery when i get the funds and beaf up the power cable from the alt to the battery as thats all still stock.

alex

hahaah competeing..i have the same amp

they make much bigger ones then that dont you worry

davo

You know the amp won't constantly draw the 100amps the fuses rate it at right?
It'd probably be flat out drawing that much current on a test tone with the gain on full.

Your better off spending the money on a better battery (Odyssey, Optima etc) than on a capacitor that have been proven to not do anything (do a search on http://www.mobileelectronics.com.au/) except take up room and lighten your wallet.

agree. get a good battery, and upgrade your alternator. last of all, up your idle - i assume that's the only time your lights dim (which is normal)

Alex wrote:hey guys,

just after some background info here.

stereo rundown
-alpine 1000wrms monoblock running 13inch focal sub
-alpine 4x125wrms 4 channel running hertz 6.5 inch splits and focal 6.5inch splits.

both of these amp are under rated and throw abit more power than that

question is, to help minimise the strain on my battery and alternator will a capacitor be beneficial? I heard for every 1000rms you run you should use a 1farad cap? Is this correct?

It does make my headlights and interior lights dim quite badly when its cranked.

Just wondering if theyre all theyre cracked up to be or whether i should just upgrade to a bigger battery?

thanks

alex

nice system - love alpine amps

bit off topic - what do you think of the Focal sub?

Sven

twilightprotege wrote:agree. get a good battery, and upgrade your alternator. last of all, up your idle - i assume that's the only time your lights dim (which is normal)

that is the answer i was after thanks guys

D3V1L wrote:hahaah competeing..i have the same amp

they make much bigger ones then that dont you worry

davo

HAD...haha..

and it depends on what class you enter DAVID! tehehe

sven '2' wrote:nice system - love alpine amps

bit off topic - what do you think of the Focal sub?

Sven

cant recommend it enough mate. It just sounds great. Soo much punch and responsiveness for a 13inch..people cant believe im running only one sub.

however if you thrash your stereo like i do, they tend to break tinsel leads easily, im onto my 3rd focal sub now. They may have fixed the problem though, because my current one has been going for much longer than the previous(touch wood)

bobbyjimmy wrote:You know the amp won't constantly draw the 100amps the fuses rate it at right?
It'd probably be flat out drawing that much current on a test tone with the gain on full.

Yeah i know, i was just surprised that it could be that high.

Alex wrote: however if you thrash your stereo like i do, they tend to break tinsel leads easily, im onto my 3rd focal sub now. They may have fixed the problem though, because my current one has been going for much longer than the previous(touch wood)

Thats why I run Rockford Fosgate, Put it in and forget about it!
The capacitors usefullness depends on the distance from your amp but if you have a close enough battery and small enough impedance you shouldn't need it although they do help reduce noise while the car is running!

tex wrote:Thats why I run Rockford Fosgate, Put it in and forget about it!
The capacitors usefullness depends on the distance from your amp but if you have a close enough battery and small enough impedance you shouldn't need it although they do help reduce noise while the car is running!

yeah looked at the fosgates...none of them take my fancy. Focal for the same price absolutely smashed it. In sound quality and output, but thats only my opinion...i HATE boomy bass.

As for the capacitors ive since heard theyre pretty much useless as you guys have said. Will eventually upgrade my battery to something like an optima yellow top.

alex

Suparoo wrote:Yeah i know, i was just surprised that it could be that high.

My old sub amp was rated at 200amps...
Came with its own ANL fuse holder.

tex wrote:Thats why I run Rockford Fosgate, Put it in and forget about it!

DD Audio for subs, Diamond Audio for components/speakers, RE Audio for amps here.

my mate had a smaller amp in his car, but he had an oscilloscope in his shed which he connected to the speaker leads, this would show some clipping on big bass thumps. a 1farad cap fixed probably 90% of the clipping. couldnt really hear any difference by ear and the old car had heaps of rattles as well. makes sense tho as an amp will clip and produce raw dc current when it runs out of juice, and first place this happens is on big bass transients, and a cap will store and release momentary power as required and faster than a battery can chemically produce the required power.
as a small aside i used to tune the amp gain with earmuffs on, isolate to one amp at a time, reduce gain, wind head unit to full noise, then increase gain on one side till it distorts, reduce till clear, mark gain level, reduce gain. repeat on each channel on each amp, then wind gain back to marked levels, remove muffs.
now cruise in the knowlege your ride sounds crystal clear on the outside and you not going to blow speakers cause you cant hear them distorting.

awesome amps btw