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help! alternator whine (and other electrical buzzing when boat is off) is making me crazy!


shawndoggy

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16 minutes ago, Slurpee said:

One possibility is application. If it’s not a marine EQ then you can get problems from the environment. I had an Audio Controls EQS in my 16 and within a year several of the potentiometer knobs were messed up enough to be giving false settings and messing up the signal. After 14 months I had two dead channels. This sucker never got wet. Just lived in a high humidity Texas environment. 
 

By the way. If you look close at those stinger cables you’ll see an silkscreen arrow on the jacket indicating direction of travel. The start of the arrow is the end with the shield grounded to the rca. Presumably that is the source and theoretically the quietest point. Follow that as best you can for best practice. 
 

I love the xd800.8. I had that driving all 8 of my cabin speakers on my ‘01. Wonderful amp. 

try south louisiana, my friend has an awesome stereo in his G, i think he uses non marine amps and is always fixing it, but again it is awesome when its working 

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29 minutes ago, granddaddy55 said:

try south louisiana, my friend has an awesome stereo in his G, i think he uses non marine amps and is always fixing it, but again it is awesome when its working 

Yeah. That conformal coating and proper adjustment controls are key. That’s why I LOVE my JL MVi amps. All digital. No manual electromechanical switches or knobs. 

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I have not decided what my permanent fix is, but here is what I have found on my 2018 A24.

I went through most of what is mentioned here and got no where to speak of. 
 

I took an old Kenwood head unit and temp wired it in and used it as my source unit. Tower speak noise was gone. 
 

I believe my issue is directly related to the surfgate beeps feeding a signal into the tower speaker amp. When I unplug the RCA from the tower speaking amps, the noise is gone. 
 

When plugged into the Kenwood unit, no noise. 
 

My next step is to find the ground for the surfgate and try to relocate it to the same ground as the amp. If that does not work, I am going to delete the factory head unit completely and do without the beeps. 

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18 minutes ago, MFknK said:

I have not decided what my permanent fix is, but here is what I have found on my 2018 A24.

I went through most of what is mentioned here and got no where to speak of. 
 

I took an old Kenwood head unit and temp wired it in and used it as my source unit. Tower speak noise was gone. 
 

I believe my issue is directly related to the surfgate beeps feeding a signal into the tower speaker amp. When I unplug the RCA from the tower speaking amps, the noise is gone. 
 

When plugged into the Kenwood unit, no noise. 
 

My next step is to find the ground for the surfgate and try to relocate it to the same ground as the amp. If that does not work, I am going to delete the factory head unit completely and do without the beeps. 

My surfgate is (was) grounded to the engine block on the port side, along with the main ground from the batteries, the blower, and the two rear ballast pumps.  By block was painted over in this location.

As part of my efforts, I regrounded the SG directly to the house battery by running a new run of 4awg from the battery to a blue sea grounding stud, which I mounted behind the rear seat near the surfgate breaker.

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20 hours ago, Slurpee said:

One possibility is application. If it’s not a marine EQ then you can get problems from the environment. I had an Audio Controls EQS in my 16 and within a year several of the potentiometer knobs were messed up enough to be giving false settings and messing up the signal. After 14 months I had two dead channels. This sucker never got wet. Just lived in a high humidity Texas environment. 

It's the desert here and we get a grand total of 7.48" of rainfall a year.  This year only about 3", which is evident when I look outside and see the smoke from the forests burning down north and south of us.

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5 minutes ago, shawndoggy said:

My surfgate is (was) grounded to the engine block on the port side, along with the main ground from the batteries, the blower, and the two rear ballast pumps.  By block was painted over in this location.

As part of my efforts, I regrounded the SG directly to the house battery by running a new run of 4awg from the battery to a blue sea grounding stud, which I mounted behind the rear seat near the surfgate breaker.

Dang. Well, maybe it is just my head unit itself. When using the Kenwood(old POS). I had no noise, running or not.

 

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Just now, MFknK said:

Dang. Well, maybe it is just my head unit itself. When using the Kenwood(old POS). I had no noise, running or not.

 

It'd be worth checking and cleaning up the grounds to the block to confirm that they are clean and tight and hit bare metal.

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22 hours ago, shawndoggy said:

I'm just wondering if the amp was backfeeding some bad mojo into the electrical system through the power and ground feeds

Your noise did sound like it could have come from a switched power supply.  A bad input capacitor, transistor, or diode could allow some of the power signal to feed back into the power line.

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Once again we are in California's chimney flue and the smoke has been pretty brutal for the past 10 days.  We didn't go out last weekend because the AQI was over 250, and this weekend looks like it may be a bust because of thunderstorms.  Ugh.

I've made the last change that I'm going to do before water testing.  As noted upthread, I've been through three EQs... a WS420sq (figured out how to let the magic smoke out), a Clarion EQS755 (takes a licking and keeps on ticking), and an Arc KEQ5 (great sound but a channel died).  @Slurpee mentioned that the KEQ might not have been up to the task from a marinization perspective. Which is a fair point, and would also apply to the clarion. A bigger gripe about the clarion is that the knobs are really small, and the sub level is on the far left rather than volume, so it's not the easiest to use (for my wife).

I've never been terribly impressed with the wetsounds WS420.  It's a great idea, but still not the easiest to use in practice.  It's also easy to mess up those double EQ knobs.

So I decided to go with a Memphis EQ this time around.  The MXAEQ7 claims to be marinized, and I liked what I saw in the pictures with dangling RCA connections rather than fixed-in-the-back-of-the-chassis connections.  So I decided to give it a shot (also about half the price of a WS420sq).

Out of the box I'll confess I was a little nervous. The fit and finish is not up to lexus quality.  However, the seals on the power and rca inputs and outputs do appear to be pretty robust.  I was also a bit concerned about not having adjustable gains on the aux input, because that had to be turned up on both the KEQ5 and the EQS755.  No idea what the sub crossover slope is either, and its definitely not adjustable.  

Nevertheless I fired it up and was pleasantly surprised.  This thing has the highest voltage outputs of any eq I've ever used.  Gains are all the way down on the cabin amp, and thankfully the tower amp has a high voltage input switch to provide a little headroom.  On the trailer it sounds really good.  I had a minor glitch with a turn off thump when I turned my dash switch off.  Overnight it occurred to me that maybe I should try running B+ and REM separately, with B+ constant, and REM only on the switch (I had tied them together on the initial install).  That totally fixed it.

 

BD40139E-3CA6-4E84-842C-501523F5D567_1_105_c.jpeg

Edited by shawndoggy
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  • 2 weeks later...

Having similar issue. I have a single amp being fed a sound signal directly from the radio, (using legit RCA cables that are NOT routed along with power cables).  I get the "blower whine" (bilge pump also an issue).  Have everything powered and grounded directly to the battery, (8 awg wiring so no resistance issues there).  I'm thinking of throwing in a ground loop isolators on the RCA feed going into the amp, purely out of desperation. 

Am i correct that your resolution was just to replace the bad amp (which may or may not have been caused by the EQ)?  

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1 hour ago, rebelinc said:

Having similar issue. I have a single amp being fed a sound signal directly from the radio, (using legit RCA cables that are NOT routed along with power cables).  I get the "blower whine" (bilge pump also an issue).  Have everything powered and grounded directly to the battery, (8 awg wiring so no resistance issues there).  I'm thinking of throwing in a ground loop isolators on the RCA feed going into the amp, purely out of desperation. 

Am i correct that your resolution was just to replace the bad amp (which may or may not have been caused by the EQ)?  

that was my resolution, but I think it's safe to say that it was kindof a weird one.  

Is your radio grounded to the same place as your amp (battery i.e. NOT somewhere under the dash?)

Is your radio's B+ (probably a yellow wire) fed from the same place as your amp (either battery directly or perko switch common post... i.e. NOT somewhere under the dash)?

If you unplug the rcas from the amp, then turn on the blower, is the blower wine present or not?

If you leave the rcas plugged into the amp, but unplug them from the HU, then turn on the blower, is the blower wine present or not?

If you disconnect the HU power and ground wires altogether, but power up the amp, then turn on the blower, is the blower wine still present? 

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Check your GAINS...set them with a noise signal at 40hz and 1khz. Set at headunit, at EQ/signal processor, and at amp. Properly set gains eliminate noise. If your already well grounded....this is where I would look.

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Finally a day on the water (we went for it even though AQI was over 200 #dixiefire). Everything worked great, all day long. No pops no whines no crackles. 

I also tried out the swift volume iPhone app and it worked great for speed based volume control. 

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