Right let's se...
 

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[Closed] Right let's see how good the knowledge on here is.. my Q asked on another forum.

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I asked this question on a pretty massive (mainly US) powerboating forum.
It was answered, correctly as it turns out, within 30 minutes. It's not a specifically boaty question so let's see how the hive gets on. I reckon you'll nail it.

Just fitted a small [Fusion] head unit to our boat and wired it to a JL Audio amp.

When I switch on the HU the amp power light comes on but but no sound and it just buzzes (internally) until I pull the RCA connector from the amp, at which point the buzzing stops and the power light goes off.

If I replace the 'amplifier on' wire from the HU with a direct 12v feed from the battery everything works as it should - so I assumed I had a faulty connection on the 'amplifier on' wire.
I remade the connection and checked the voltage and it's >12v but when I connect it back to the amp I'm getting the original problem again.

I can't figure out what could be different about the feed from the HU to a direct feed from the battery.
I could get around the issue by triggering a relay with the 'amplifier on' feed from the HU which switched a direct feed from the battery.... but that seems a bit clunky.

Any ideas what's going on?
__________________

I will add that the amp is powered directly from a battery and the 'amplifier on' wire probably just triggers an internal relay in the amp.
There are two batteries in the boat.


 
Posted : 02/05/2017 7:42 pm
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Conti Vert Pros.


 
Posted : 02/05/2017 7:45 pm
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Louise


 
Posted : 02/05/2017 7:46 pm
 Drac
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Try the HU feed make sure it's going to the same battery as the amp.


 
Posted : 02/05/2017 7:47 pm
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Is it missing a Dolby?


 
Posted : 02/05/2017 7:47 pm
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metalchicken ? 🙂


 
Posted : 02/05/2017 7:48 pm
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Big hammer.


 
Posted : 02/05/2017 7:49 pm
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metalchicken

No. It's a baby robin, obviously.


 
Posted : 02/05/2017 7:49 pm
 MSP
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Yes you will die, eventually.


 
Posted : 02/05/2017 7:51 pm
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Does it have shoes? If yes, wee in them. If no, buy it a pair and then wee in them


 
Posted : 02/05/2017 7:51 pm
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[quote=ninfan ]Is it missing a Dolby?


 
Posted : 02/05/2017 7:52 pm
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Is the powerboat on a conveyor belt?


 
Posted : 02/05/2017 7:53 pm
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Try the HU feed make sure it's going to the same battery as the amp.

BOOM!

Drac, you is [one of] da manz. 8)

4 minutes..... *bows*

As I was sort of testing the setup and had the head unit attached to the existing battery and had connected the amp to a new battery that was sitting on the deck.
Shows just how much I know about electrickery.

STW Chat Forum remains at the top of the pile.


 
Posted : 02/05/2017 7:53 pm
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From your comments I am really concerned about the integrity of the amplifier ground. I'd hate to think the amplifier's only reference to true ground is the RCA shield to HU termination. That could do expensive damage to the HU and wouldn't do the amplifier any favors either.
Do NOT unplug/plug-in RCAs while the audio components are connected to power.
Start by disconnecting the RCA link, re-check the supplies, and most importantly the grounds, and first get the amplifier to correctly turn On/Off without the RCA connection.
Make sure that both the HU and amplifier are referencing the identical physical supply point and the same with the physical ground point.
I think your problem will likely clear up before you would have to take additional steps related to the turn-on/off circuit.


 
Posted : 02/05/2017 7:53 pm
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Sounds like a grounding issue.

#Jambafact


 
Posted : 02/05/2017 7:53 pm
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Yes David is right on point here, totally agree

Jim


 
Posted : 02/05/2017 7:54 pm
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Very good DT, very good!

* makes note to change username


 
Posted : 02/05/2017 7:55 pm
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Dammit, beat me by seconds. Grounding issue. my vote is for the HU. HU doesn't have a proper ground, and is earthing through the RCAs to the amp chassis.

EDIT: Dammit. Too slow. and slightly wrong. I was assuming 1 battery and negative earth tot he chassis. Without thinking about the reality of this with what-a-boat-chass-is-probably-made-of-it's-not-a-bloody-car.


 
Posted : 02/05/2017 7:56 pm
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The HU and Amp don't necessarily need to be on the same battery, but they do need to be on the same ground. All battery negatives and grounds of all electrical equipment on board should be bonded together.


 
Posted : 02/05/2017 7:56 pm
 Kit
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Does it come with a crown race?


 
Posted : 02/05/2017 7:57 pm
 Drac
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Drac, you is [one of] da manz.

4 minutes..... *bows*

It would have been quicker but I was playing with the dog while reading your reply on the other forum.


 
Posted : 02/05/2017 8:03 pm
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Have you tried turning it off and then back on again?


 
Posted : 02/05/2017 8:05 pm
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Drac, you is [one of] da manz.

4 minutes..... *bows*


7 mins according to STW, just sayin (might have seen it a bit later)

Our solution last year on boat electrics, drop it off at local Mastercraft dealer and pick up when they fix it, £1000 the lighter.


 
Posted : 02/05/2017 8:12 pm
 Drac
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7 mins according to STW, just sayin (might have seen it a bit later)

Maths isn't your strong point, just saying.

POSTED 34 MINUTES AGO

POSTED 30 MINUTES AGO


 
Posted : 02/05/2017 8:18 pm
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drop it off at local Mastercraft dealer and pick up when they fix it, £1000 the lighter.

It was just a fuse, then? 😀


 
Posted : 02/05/2017 8:34 pm
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Drac, 5 mins then

Tillydog, close but no, that cost £1500 the year before. This was something else unspecific that wasn't quite as big as a fuse but was also only available by special order from the USA.


 
Posted : 02/05/2017 8:56 pm

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