37 replies to this topic

[Cyberpunky]

It you think a cap will make a difference to sound it probably will, but wether it does make any difference is another matter. Personally I think caps are just audio jewellry. They look purdy but cant be heard to make a difference, despite what ppl tell them selves IMO.

Anyway there are countless threads on this subject on the net, and most ppl tend to think they do nothing and some can even back it up with the maths/physics. RC was one of the first to use a cap(he coined the name "stiffing cap") and he thinks they do nothing in this day and age as most amps have plenty of caps on board and are properly designed.

Just my $0.02 worth
peace
Cyberpunky

[suparoo]

Im pretty much in aggreance mostly with the Caps are useless, when the car is running they would be good to smooth out the rippled from the rectified AC from the altinator, but when the cars not running etc, you have a battery that is Pure DC, and car batteries are desined to deliver over 300A instantaniously. so as far as im concerned, good altinator, good battery, good wire, and you dont need a Cap.

[Tiger]

I like that last note, thanks suparoo.
Well, the advice has been amazing... thanks to everybody in this thread... even the guys who decided 2 cents worth was enough.. well, every penny counts! Thanks again

[Pyroay]

I have a 97 Ford falcon and am running a optima sealed battery in the boot (as well as the standard one up front) and a 1 farrad cap. I am running 4 amps with a RMS output of around 2000rms. I have no dimming with all of the lights on, heater on full anything at at all running. Further I can run the system with the car off for ages without any voltage drop (measured using a volt meter). With the cap and battery only 80cm from the amp power terminals there is a sold 13.4 volts at all times. If i crank the system as hard as i can it drops to 13.1 - 13.2. AWESOME.

Without the cap voltage drops to 12.1 - 12.3.

I guess at the end of the day it depends on how sensitive your amps are to voltage drop. Some amps (particularly brands like soundstream) get clever with there power ratings for IASAC competition purposes and the difference between 12 volts and say 13.5 can be 2 x 20rms as opposed to 2 x 200rms. Thats because many car audio amps have un-regulated power supplies.

I have had systems with and withour caps and I definately think on eis worth the money. Nothing too fancy like running 1 farrad per amp. But a worthwile investment in my mind and i agree with some earlier comments, they doo look good.

[Bassaholic]

Quote

Originally posted by Pyroay:
Some amps (particularly brands like soundstream) get clever with there power ratings for IASAC competition purposes and the difference between 12 volts and say 13.5 can be 2 x 20rms as opposed to 2 x 200rms.  Thats because many car audio amps have un-regulated power supplies.

The ratings may differ, but the actual power output will not differ by that much - Very few car audio amplifiers have un-regulated power supplies and even then the difference will not be worth worrying about - Remember you need 25% more power to even make 1dB of difference and twice the power to make 3dB - and this is assuming no nonlinearities - real world may require more power..

[fr0st]

Electronicly the cap will smooth out a bit of the alternator ripple but from what I've seen its not enough to make an audible difference. I made a prototype amp that I tested on a friends system with a farad in the boot and alternator harmonics still came through. This was probly my fault since I didn't filter the power supply but for most amps it won't make a scrap of difference.
As for making the bass tighter, it probly would but to a lesser extent. IF it has a lower ESR than the battery it would be the first to supply current to the amp. Once its flat it will draw craploads of current to recharge but over a short period of time along with the current draw from the amp. Basicly if you system can flatten the cap your better off without one.
Oh.... when the caps charging again it'll draw alot of current so u get voltage drop. when it gets near the voltage it draws less current so u get less voltage drop and so on. On top of the cap discharging its probly gonna draw excess electricity than without it.
If I've said anything thats wrong correct me

[suparoo]

if you wanted to effectivly get rid of altinator noise with a capacitor rather then these 1 farrad caps, youd actually need more along the lines of a 10pico farrads or so, to act as a low pass filter. but a lil 3cent cap? naaa big boys cant have that, need something big and looks cool

[fr0st]

inductors are low pass, caps are highpass... well i'm pretty sure anyway.
Either way large caps don't do squat