What in the hell?

[cneelyii13]

Hey, people! I am new to this site so take it easy on me. I have been installing car stereo systems for myself and others for over 10 years now. I have also been asked to consult on some installations, but just local. Nothing big. I have recently run into a problem that I cannot solve, but I think that I have an idea. I believe that it has to do with my voltage settings at my head unit, but you all help me on this. This problem is madness.

I have a Kenwood Excelon Head Unit, I can't recall the model number at this time. I also have a MTX 204 4-Channel amplifier pushing a custom built component set, and a MTX 302 2 channel amplifier that is pushing a single MTX 5500 8" subwoofer. This set-up is all that is left after I blew a similar subwoofer, a MTX 250D class subwoofer amplifier, and fried a sub pre-out on a newer model excelon head unit.

Anyway, my first install included the original Kenwood Excelon head unit and the MTX 204 4-channel amp. I just wanted one amplifier in my truck, because I had heard the the grounding properties in a truck really sucked. I had everything hooked up and working. I put the rear channel on the sub pre-out of the head unit. I would notice that everytime I would come to a stop, the head unit would flash/blink. I never thought anything of it. I did think that it could be a possible voltage problem, but everything was working fine. Everything was working great for a few months until all hell broke loose. One day I went to start my truck and all I heard was this loud continuous bass note that didn't respond to the volume knob. I had to yank the RCA cables from the amp to make it stop. It scared the snit out of me. So after waiting about 10 minutes, I hooked the RCA's back to the amp and unplugged the subwoofer wires. I looked at the wires and tried to reinstall them and a spark like from a battery connection happened. I was shocked so I tried it again, and the same thing happened. At that point, I realized that I had live voltage coming through my system, but I didn't know from were exactly. The voltage had fried my subwoofer.

I installed another amp, MTX250D to power a spare subwoofer that I had. I hooked it up to the sub pre-out rca, and the same thing happened. I was able to save my sub this time, but not my amplifier. I realized then that it was my sub pre-out that had a voltage problem, so I replaced the head unit with the newer model Kenwood Excelon, but I left the 4 Channel amp in play. I connected the sub pre-out to the rear channel, and hooked up the sub. I had sound for about a minute, and them it became distorted all of a sudden, and then finally went out. I figured it was just the rear channel of the amplifier, so I installed another amp and plugged it into the sub pre-out, the same thing happened, so I now run it off of the rear pre out from the head unit, but that limits what can be done with the system. I still get that flashing/blinking head unit at every stop. What do you all think it could be?

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[NewAgeKing 5,000+ posts]

Shit.. clifs?

 

[99grandprixGT 5,000+ posts]

Shit.. clifs?

x2

 

[shaneb 10+ year member]

Welcome to the thread.

I am havin' some trouble understanding exactly what the problem is...try and put it in not so many words?

 

[funkyab 10+ year member]

happened similar in a home theater install i had once. You are def getting dc coming through your rcas. You need a new head unit.

 

[funkyab 10+ year member]

Welcome to the thread.I am havin' some trouble understanding exactly what the problem is...try and put it in not so many words?

he is getting dc coming through his lines, making his sub hum and pop and frying his amp.

OR... the dc could be coming through your amp but unlikely if you already replaced it.. Im 99% sure HU is the culprit.

 

[Louisiana_CRX 5,000+ posts]

check your grounds.....

 

[n2audio 5,000+ posts]

fyi--

dc is not audible

 

[funkyab 10+ year member]

fyi--dc is not audible

the humming says to be ground loop issue of course but dc coming through the rcas is all i can think of unless of course his pos is grounding out along its run somewhere.

 

[n2audio 5,000+ posts]

dc goes..."thud" - once, that's all.

the cone pushes out, or pulls back (depending on polarity) and sits there until the voltage is removed. There is no hum.

 

[kush-divinity 10+ year member]

Your RCA's may be pinched together, or one may be skinned and touching ground somewhere.

But, don't keep testing it with amlpifiersd and subs man, shit, go bassless for a bit.

 

[da box king 10+ year member]

fail.....dont ever type a book again....

 

[Jeepjones85 10+ year member]

My buddy had that happen to him one time, The cd played blew up after some rewiring he did. The sub was loud as H*ll like a big buzzing sound, So he turned the ignition off quick. But he got lucky and just replaced the cd player and it was fine.

 

[shakinghorizons]

I got the same deck, with the same problem, besides the dimming, I went crazy trying to figure it out, eventually I had to ground my outer connector of my rca's to my deck chassis, sounds REALLY messed up but it's the only thing that worked. For this reason, I will never buy a kenwood again.

 

[cneelyii13]

Thanks to you all! I plan on ripping everything out since it is all damage in one way or another, and starting from scratch. I plan on running power and grounding my head unit separately, because I think that the factory wiring is funked up. I had the same head unit in my Jeep for several years with no problems. I plan on doing it soon before I blow up. Oh yeah, my second amp has just fried! ****!