Amp not getting enough power; alternator fine

[JohnCWms27]

Recently my music started to cut off and on, off and on, and then just ceased to play altogether. Let me back up some...i have a 2-channel amp running my car speakers (no subs at the moment). I have a capacitor tied to that amp. with car off and key in ignition, it reads around 12V, as it should. but when i start the car, the voltage on the cap varies between 9 and 11 Volts, causing the amp to not have enough power to play my beloved Tupac. took my car to advanced Auto and got the alternator and battery checked - they're both working fine. what could the problem be?

[96AvalonXLS]

I would start by removing the Capacitor. Then give it a shot. If it still doesn't work properly it could also be something wrong with your voltage regulator if your car has one.

Good luck!

[Delay_FTB]

What amp is it?

It sounds like something is loose, connection-wise. Or perhaps the amp is going into protect for some reason.

Your voltage shouldn't DROP when you start your car, it should increase (to around 14 volts). Lose the cap, you probably don't have enough power to merit having it anyway.

What car is it?

[JohnCWms27]

I checked my connections again and found the ground was kinda loose. After tightening it up my cap is reading almost 15V and music is playing loud and clear! stupid ground connections....