kenwood hu clipping?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=115418
Printed Date: May 13, 2025 at 7:55 AM
Topic: kenwood hu clipping?
Posted By: rahn
Subject: kenwood hu clipping?
Date Posted: August 01, 2009 at 5:12 PM
I am not a pro, but not a rookie either as I have done quite a few of what I would call average installs. Anywhooo....on to the problem.
I installed a Kenwood KDC-MP438U Head unit, an Alpine MRP M500 mono amp and a single 10" sub in a boat for a friend. It already had some Sony 6.5" marine speakers in the stock locations that seem to do OK from the power built in the HU.
The problem is, when you turn the HU up to 23 on the volume control, it cuts out. I thought it was the sub amp clipping, but today I went over and turned the gain all of the way down on the amp, just to see if I could get it to quit.
The boat has a dual battery setup with a switch for Battery 1, Battery 2 or both. The battery that the amp is hooked to shows 12.6V @ rest (not running) but this thing clips whether it's running or not. Is this a voltage problem supplying the HU?
The amp is mounted under the driver's console and has plenty of air space, but I don't think the amp is the problem. Could I just pick up 12V @ the amp and run it to the HU? I would think the 8 ga. wire I have running the amp should be able to supply power to the HU as well if it isn't getting enough from the factory 12 switched source.
I've never had one give me such a fit before and I'm stumped. I appreciate any ideas you folks may be able to drop off. Thanks in advance!
Replies:
Posted By: DYohn
Date Posted: August 01, 2009 at 6:32 PM
Cutting out is not the same thing as clipping. Clipping is distortion; cutting out is turning off. When you "turn the head unit up to 23" WHAT cuts out? ------------- Support the12volt.com
Posted By: i am an idiot
Date Posted: August 01, 2009 at 7:26 PM
You need to check the voltage getting to the radio. When checking, the radio must be turned up to the point just below it cutting out. Red meter lead on the Yellow wire of the radio, black meter lead on the chassis of the radio. It being a boat, you may have to upgrade the ground for the radio. If you have no meter, run a 12 Ga. wire from the radio's ground connection directly to the battery. ------------- Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB
Posted By: rahn
Date Posted: August 02, 2009 at 9:58 AM
DYohn] wrote:
Cutting out is not the same thing as clipping. Clipping is distortion; cutting out is turning off. When you "turn the head unit up to 23" WHAT cuts out?
The head unit is what is cutting out, which in turn shuts everything down momentarily.
Posted By: rahn
Date Posted: August 02, 2009 at 10:01 AM
i am an idiot wrote:
You need to check the voltage getting to the radio. When checking, the radio must be turned up to the point just below it cutting out. Red meter lead on the Yellow wire of the radio, black meter lead on the chassis of the radio.
It being a boat, you may have to upgrade the ground for the radio. If you have no meter, run a 12 Ga. wire from the radio's ground connection directly to the battery.
I follow what you're saying and never considered the ground, but that would be an easy fix. Do you mean to check the voltage on the RED wire rather than the yellow since the red is the 12v switched rather than the memory circuit?
Posted By: DYohn
Date Posted: August 02, 2009 at 10:32 AM
Check the voltage on both. The yellow wire is the main power supply to the head unit. Also, make sure none of your speakers are shorting out, which will cause the head unit to shut down in protection mode. It is possible the speakers are fine at low volume but that one or more voice coil is shorting when you turn it up loud. ------------- Support the12volt.com
Posted By: icearrow6
Date Posted: August 02, 2009 at 5:03 PM
Check the impedence of the 6.5s that are already there.... I've seen some 2ohm marine speakers....
But this only means that the problem was there BEFORE the install. Treat it as an existing problem prior to the install and what to you get? Possible bad HU IF the speakers are ok.
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Posted By: i am an idiot
Date Posted: August 02, 2009 at 5:28 PM
If the radio is less than about 20 years old, the red wire is simply a low current trigger wire to let the radio know it is OK to turn on. 20 years ago the yellow wire was known as the memory wire. It only kept the clock running and kept the preset stations in memory. Newer radios pull next to no current on the red wire. But as DYohn stated, check both. If either wire is dropping significantly, this can be the cause of your troubles.
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Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB
Posted By: rahn
Date Posted: August 02, 2009 at 5:29 PM
Gotcha. I wasn't aware of that! I'll check both and see what's up. Thanks for the info everyone! 
Posted By: rahn
Date Posted: August 03, 2009 at 1:30 PM
Well, thanks to everyone's advice I have fixed the problem with the boat. The ground connector on the amp was loose! I also ran constant 12v and ground from the battery and the boat now rocks! Thanks again!
Posted By: i am an idiot
Date Posted: August 05, 2009 at 7:22 AM
rahn]W wrote:
ll, thanks to everyone's advice I have fixed the problem with the boat. The ground connector on the amp was loose! I also ran constant 12v and ground from the battery and the boat now rocks! Thanks again!
We are glad you got your problem taken care of. I see you got it taken care of on the 3rd of August. We hope your friend is safe in his BOAT. ------------- Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB
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