So I just finished installing my EQ and have met a new problem, my speakers all have a low hiss to them. The hiss will remain constant at any volume, and even when I remove the RCA's from the Headunit to the EQ but when I remove the RCA's from the EQ to speaker amp the buzzing will stop. These are brand new Knu Krystal wires I'm using for the 4 chan amp so I don't think it's the RCA's. Checked my ground and it is well sanded and connection is firm to the metal. Tried lowering the Gain on the amp and that did make it quieter but the hiss was still there in the background. Another problem I'm having is that when I turn off my car my sub makes a kind of popping sound. The EQ is grounded into the HU's ground wire. Any help is appreciated.