Final stage constantly goes to interference. HELP!!!!

Hi guys, I have a huge problem and I’ve had a new power amplifier (Lanzar Opti 2×500) for almost 3 weeks and for a few days it’s always been a problem no matter how loud/long I listen to music. My previous power amplifier (Hifonics Brutus) did it until it gave up its mind. Now my question: Did I possibly have something wrong connected??? Did I make a little sketch so you can see how I connected everything. Maybe something really is wrong. ill the new power amplifier not to scrape again I also noticed that the power cap only lights up once in a while. Is the possibly defective? Does a power cap always have to light up??? Components of the system are: Power amplifier: Lanzar Opti 2×500 2 channel power amplifier 2 x 750 watts at 2 ohms 2 x 500 watts at 4 ohms subwoofer (as free air installed): Ground Zero GZUW 15 38cm Subwoofer 1500 W RMS 2 x 3.6 ohm 75mm Vibration coil Xmax 25mm double centering Powercap: Dietz 10 Farad Thanks for your Answers in advance. MfG Markus