When you say earthed I imagine that means grounded. Doesn't the cap only have two terminals? on connects from the battery and one goes to the amp where would you ground it from??EF MAX said:
I am not a great lover of caps but they do help some people out. It is worth noting that the better the amp the less need there is for caps. Often I see caps on systems that have very good branded amps, but their owners have been seduced by marketing bullshit.
As for fitting them. Safety is a real key issue here. Done wrong and this things can seriously harm both you and your car.
They should be mounted as close to the amps as possible. They should be earthed well and if possible to the same point as the earth on the amp/s. You need to take the power supply from the battery to the +ve side of the cap, then take a power feed from here to the +ve input on your amp.
SAFETY.. can't stress it enough, these things if shorted out can torch your car as if you set fire to it and poured petrol over it.. SAFETY...
Hope this helps... EF MAX