Wiring the Stereo This Weekend

I'm going to be wiring up the stereo this weekend. I've spent lots of time scouring the forums and have arrived at this diagram. Anybody see any gotchas? Any thoughts are appreciated. Thx!

assuming you've run the numbers and 8awg is sufficient for your amps. I usually go 4awg just as overkill, but not necessarily necessary if the runs are short and the loads aren't heavy.

Only thing I don't see in the diagram is how you are going to fire up the system. May be just as simple as turning the HU on at the deck, but usually people add a switch to fire up the red lead into the deck and then let the deck fire up the rest of the system through the remote turn on lead (which would go to your relay in your diagram.

Oh also is a 2A fuse sufficient for your HU? Usually HUs (modern ones anyhow) have 10A fuses.

Biggest thing I see, would be to run the amp grounds and head unit ground directly back to the battery. Avoid grounding to the buss bars. It can cause potential noise interference issues. Even some of the manufacturers have finally started doing this in new boats.

If the distances are very short then you are okay with the cable that you have documented, but since you are already using 4-gauge and 1-gauge cabling, I would upgrade the amplifiers +/- main supply to 1-ga. and upgrade the amplifiers +/- extensions to 4-ga.

I would suggest using the indicated "helm switch" to switch the head-unit on, then let the head-unit turn on the amp. As if now, the head-unit is going to wake up when the battery switch is turn to ON, yet the amps are controlled through a switch.

Originally Posted by Fixable

Biggest thing I see, would be to run the amp grounds and head unit ground directly back to the battery. Avoid grounding to the buss bars. It can cause potential noise interference issues. Even some of the manufacturers have finally started doing this in new boats.

This is a very good point. However, I would ground the HU and any other sources or processors to the distribution block for the amplifiers rather than the helm block. I would do the same on the positive side and keep the master disconnect switching in place. When it comes to thwarting noise, having a single point of ground reference between all audio components in the signal path is more the key, and this common reference point doesn't necessarily have to be the battery post. Same with the positive side.
If using the main ground buss bar, it needs to be a monster. I don't believe it's needed. I hate to see too many terminations stacked on any single battery post but they do make HD post expanders.

^Very true.

Thank you all for sharing your expertise. I made changes to the diagram based on your input. I think I captured all of your thoughts and made some clarifications as well.The only thing that I didn't change was the added stereo fuse block/ground buss that will be installed under the helm (Note: this is not the existing boat buss).

As a point of clarification, only boat operation items run off the start battery and only stereo devices run off the stereo battery. All stereo grounds now terminate at the stereo battery ground (-) post instead of a ground bus. All stereo power originates at the switched lug on the stereo battery side of the master switch. One exception, the HU memory power will originate at the (+) side of the stereo battery.

I left the added stereo fuse/gnd block under the helm because I wanted a source of pwr and gnd for future expansion (BT, WiFi, EQ, etc). I was hoping to not have to route new wiring each time I added a device. I understand the reasoning to run pwr/gnd all the way back to the batt for each device (It's like star grounding a tube amplifier - all grounds route back to a single lug). However, IF I can get away with maintaining the block, I want to give it a try. I can always remove it later if it is a source of noise. Thank you David and Eric for your input on this.

I changed the way the system, "fires up". A switch will supply power to the HU and the HU remote turn on will power the relay which will turn on the amps. Thank you TigeMike and Shawndoggy for your input on this.

I wanted to install wire in sizes as recommended, but I am trying to save a little $ by using up some 8 & 4 AWG wire that I have had sitting around for too long. The runs are pretty short since both batteries, amps, main switch, ACR and added storage compartment fuse block are all right next to each other. For example, the 4 AWG run from the main switch to the amp fuse/distro block is 4 ft and the 8 AWG amp extensions are 18". The longest run is the 5 ft x 8 AWG trunk line feeding the new fuse/gnd block under the helm.

Thanks again for your input. I appreciate bouncing this off of y'all.

Here's a new diagram.

Finally! Finished all of the power wire runs and connections. I'm pretty tired of crawling in and out of the observer's compartment and underneath the helm. All is well except (and I'm embarrassed to even share this) I had the batt cables reversed on the stereo batt when I first connected it. There was no indication that something was wrong except the head unit fuse kept blowing as soon as the circuit was energized. Frustrated, I turned to my boat audio mentor, the Internet, and searched for clues. All of the information that I found was pointing to a dead HU. More frustrated I thought to myself, "So much for a budget system" thinking I now had to replace the HU. Needing a break, I figured I'd leave the HU issue for a while and test the batt switch. I turned the dial from "ON" to "Combine" and the switched arced a brilliant flash. That seemed strange. Then I heard hissing. I quickly turned the dial back to "OFF". I then realized what had happened. Crossed cables. I reconnected the batt cables correctly and everything powers up nicely now. I'm very thankful that nothing fried. Man, thank goodness for fuses!