white scooby

just ordered an optima yellow top battery n got 0.5 farad power cap in for four genesis amps anyone got any ideas how many power caps i need?? or is this enough??

BigRed

General rule 1 farad of capacitance to 1 KW audio.

white scooby

best get some more then!! if 1 run a couple of 1 farad caps whats the best way to wire them??

Shifty

In parallel with the power supply, as close to the sub amp(s) as possible.

Steve.

white scooby

at the mo i've got from the battery to the cap from there to a dis block going to the amps so how would i include another cap??

Shifty

Assuming you've got two sub amps, two other amps, and two caps I'd do this:


Battery(+)______Dizzy________(+)Sub amp(-)__
(-) Block | |
| | | | Cap_____________Ground
Ground | | |
| | |________(+)Sub amp(-)__
| | | |
| | Cap_____________Ground
| |
| |
| |_____(+)Other amp(-)____Ground
|
|
|_______(+)Other amp(-)____Ground

Seems that diagram only works in a fixed width font, so click on "edit message" above to see it how I intended.

Steve.

chiark

If you want a hand mate, let us know. You've got the number and I'd be happy to help... 1F per kw is about the going rate. I'm rather "overstocked" on capacitance at the moment as I've got 2.5F... Only need about 1.

Cheers,
Nick.

white scooby

nice one mite give you a call box is trimmed up put my alpine changer in the middle hole looks top!!

white scooby

if you've any spare power caps you want to sell give me a shout!!!

chiark

Need to decide what I'm doing, but I've definitely got 1F cap spare.

David_Wallis

whitescooby.. what year is your scoob??

David

chiark

It's a MY00 STI if I recall correctly - looks wonderful and sounds fantastic

white scooby

its a my00 with sti graphics not an sti!!! yet!!!! thats coming next!!!!

white scooby

Nick if you've got that 1F cap spare i'll take it off you if its for sale!!!

David_Wallis

What area of leeds are you in?

David

white scooby

South Leeds near rothwell oulton n woodlesford

David_Wallis

Ahh.. Thats why I havent seen you about (roundhay)

matty01

What improvement is gained by putting a 1F capacitor inbetween positive and earth on an amp please as i've never heard of this before?
edited to say, aha..is it to facilitate a 'reserve of power'for particularly bassey notes ???


[Edited by matty01 - 6/15/2003 11:26:34 PM]

[Edited by matty01 - 6/15/2003 11:29:07 PM]

chiark

Matty-
hole in one

matty01

Buzzin', cheers.
Presumably i can fit it accross the positive and negative terminals on the amp itself can i ?(just for ease of fitment)

[Edited by matty01 - 6/16/2003 9:21:58 AM]

chiark

I wouldn't, no. earth it using as short a cable as possible.

Also, bear in mind that you need to charge and discharge these things through a test lamp or a resistor. Connecting an uncharged cap to the battery is a surefire way of ****ting yourself up big style. The thing has an equivalent series resistance of milliOhms, and current drawn = voltage / resistance.. At 12 V and 0.001 ohm, that'll mean it'll try to draw, oh, around 12000A.

Charge a cap by using a resistor in series.

NB - the maplins 1F capacitor has electronics to sort all this out for you

Cheers,
Nick.

David_Wallis

also watch out if you ever get a flat battery and try and jump start the car..

David

matty01

Ahh,.... i think i'll stick to my simple arrangement of amp and sub unless there's a DRAMATIC improvement in bass response,is there?

Shifty

You can connect a cap directly onto the power terminals of an amp - some amps (Rockford for sure) actually have double terminals specifically to let you do this !

Steve.

David_Wallis

you still need to charge it properly.. as this is no different to across distribution block or battery...

Proper sized power cable also helps with 140db+ bass

2 Gauge anyone ??

(ive gone back to four now!)
David