We'll I just about finished my stereo installation on my boat this weekend, but am having one issue...
My system description: I have the RCE front & rear out from the HU fed into a HD600/4, which drive 8 cabin speakers. I've run an RCA cable from the front channel pre-amp out on the HD600/4 to an XD400/4 to drive the tower speakers. The XD400/4 is setup in bridge mode to drive just two tower speakers so I had to use RCA splitters to retain L-R stereo on the tower (manual recommended this configuration). I also have an XD600/1 driving the sub off of the RCA sub output on the HU. The HU is not driving any speakers anymore. I cut those wires and ran them to the HD600/4. Pictures of the installation are below (I haven't mounted the board to the side of the boat cause I'm having a static noise issue).
My Static Noise Issue: I'm getting static noise on the RCA front and rear outputs from the HU. If you increase the gain on either the cabin amp or the tower amp, the static noise gets louder or quieter accordingly. The level of this static noise stays constant when you increase/decrease the volume on the HU. I disconnected the RCA cable running to the RCA FRONT OUT on the HU and plugged it directly into my iPhone and the static on the front four speakers and the tower speakers (which are driven by these RCA outputs) disappeared and sounded amazing. So, I know the cabin amp and the tower amp can produce a clean sound without static noise.
The three amps are powered by the distribution block in the picture above (4 gauge wire to each amp and 2 gauge wire to battery). The HU is powered from the yellow and black wire that connects to the amp right next to the HU (this is how the factory drew power for the HU. I tried running those wires to the power distribution block, but it made no difference on the static noise. The yellow wire, which I think is the power wire for the HU, is described in the manual as the "MEMORY back up" wire??? The wire, which the HU manual describes as "RED IGNITION SWITCH (B+)" runs to a blue and white wire in the factory wiring harness, which I assume runs to the ignition. I'm considering cutting out that white factory connector on the backside and coupling the power wires and ignition wire directly. Could the noise be entering through the AUX IN RCA cables (I have not made any changes to these connections from what the factory did). I ordered the boat with all speakers pre-installed, stereo option 1, and the factory sub and amp (I removed the factory amp).
Why is my HU generating this static noise on the RCA outputs? It's not awful, but it is annoying enough to bother me and my wife even noticed. Any thoughts/comments would be appreciated.
Edited by Cory, April 21, 2013 - 05:43 PM.