ok so i bout this capacitor http://www.sonicelectronix.com/item_...002TM-CAP.html and i charge it with a resistor before usage....the voltage went to around 8.5 volts. i remove resistor and connected power directly...(everything was connected correctly grounded etc) the voltage when car is on without music playing (ACC) reads about 14-14.2 volts and when i play my music it drops to as low as 10 volts then goes back up to maybe 12 volts, then 11 volts, then 13 volts continuously....i know that when i am playing my music there is a possibility that voltage drops from 14 volts if only a little on capacitor readout. But TRUST ME there has to be somthing wrong bcuz there is no way the amp/subs that i have a able to do this. I have a SPL 620 watt amp http://www.sonicelectronix.com/item_...L+DK2-620.html .

....please dont worry about hardware (amp etc) i knw it suck and alla dat....i jus wanna knw y is this happening if anyone knows or has an idea....o yeah i have upgraded the big three with 0 gauge and evrything else is 4 gauge

 

idk if its supposed to stay at 14. mine goes from 11.8 or so with the car on but not started. when i start the car it then goes to 14.5 or so then drops when the bass hits. im not sure though, just wanted to let you know ur not alone!

 

that small of equipment shouldnt bring it down that low. I'd have ur batt and alt checked it should stay around 12.6 or so

 

How do you have the cap wired? Is it in parallel with the amp? Could be the way it's wired, or you have a bad cap. Did you let it charge only to 8 Volts or did it go any higher?

 

Like Brian said, with that little bit of equipment, your voltage shouldn't drop below maybe 13-13.5 or so. If you're dropping below 12.5, you could really hurt your amp. I would NOT push your system until you figure this out.

My suggestions:
1. Pull the cap. Grab a DMM and watch the voltage at your amp. If it's still dropping down low, then you know the problem is not your cap (even though you shouldn't need it).
2. Get your alt and batt tested.