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Amp going into protection!

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Old 07-17-2009, 04:26 PM
  #1  
50 Watt CAFz'r
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Amp going into protection!

Hi all,
i hooked up my new amp to my new speakers with a new xover, on my 1 year old Kenwood DNX8120. that worked fine when connected through a Metra gmos-04 adapter for chimes to work. connected through my HU's rca out front and rear! with the oem speakers and amp (Bose or should i say blows).
the first thing that happened was the tweets went bye bye.. i did not notice right away. may 4mins after initial start up. when i was checking to see if all was ok.
so i removed them from the truck. i then found my HU was producing a very loud whine when the ignition was on but engine off (worse with engine running). took it out of the truck and in for repair. i hooked up my ipod to the front amp and after about 45min - 1hr the amp goes into protection. after a little while it would come back. than out again.. i did remove and test every single wire in the system and found nothing wrong. this was done after the tweets died. im taking the amp to Chris (great guy) at S&S Electronics tomorrow to bench test the amp.
is there a way to test the xover?
also was wondering if having removed the tweets and not put anything in their place would cause the amp to go into protection!
the amp is a Arc KS 300.4 bridged
the xover is a CDT MX-1000
all speakers are CDT

Ross is replacing the tweets under warranty for me!

any help is appreciated.

thnx
Dan
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Old 07-17-2009, 04:44 PM
  #2  
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wow
You probably need it to be professionally checked prior to power-up as it could be a number of things... no tweets shouldn't shut down an amp but it could damage a passive xover

do you have a digital multimeter and do you know how to use it??
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Old 07-17-2009, 04:47 PM
  #3  
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yes i have a multimeter and yes i know how to use it!
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Old 07-17-2009, 08:39 PM
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Originally Posted by nghtrdr
Hi all,
i hooked up my new amp to my new speakers with a ...<snip>

any help is appreciated.
thnx
Dan
It could happen depending on the crossover design. With no load on the HP ouput the reactive crossover components could go into resonance. I have had this happen before though it did not shut the amp down. The capacitor in the crossover actually began to ring out loud, easily heard over the music.
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Old 07-17-2009, 09:31 PM
  #5  
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^ ouch!!!
kevmurray is correct !!!
my goodness I am just not hitting on all cylinders, on the passive crossover I just built if the tweeter were disconnected... then there would be a short through the inductor and that is a simple second order linkwitz riley 12dB slope affair


Yes the disconnected tweeter can be a big deal

turn off the system, disconnect the speaker wires, read the resistance of the channels and that should tell you if there is a short. Check the resistance to ground to the + and - to each speaker set as well.

basically you have a curiosity that causes bad things to happen, the goal is to find what is working correctly and what is not. Use spare speakers to verify the amp isn't monkeyed up for instance. Bottom line is a single copper strand could be causing a short or ground condition and you may have to do a wiggly-jiggly to verify the quality of each connection, also you could have a low system voltage or a crummy RCA solder point on the amps input... the fun ones are problems that only show up when making a left turn or hard braking.
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Old 07-18-2009, 09:47 PM
  #6  
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ok
took the amp in to S&S this morning and had it tested for several hours. while waiting i connected my ipod to the rear older Kenwood Kac8401 amp. then drove to Selective Sound to talk to Davis about a few things. also maybe score some used tweets for a few bucks (which i did). while on the way i found the right rear speaker was not working. it did come on by itself though. i stopped to check and found i had no stereo separation from right to left at all. if i removed the rca from the right channel before the Y adapter all would go out. disconnecting the left did nothing. got the info from Davis and some DB tweets and headed back to get my amp with a stop or two in between. amp showed no signs of problems at all the whole time it was bench and pushed in bridged mode (which is how im using it). had them check the rear amp and decided it needed work so left it there.
connected my ARC back up in the parking lot, but alas i forgot the spade connectors at home. so i could not hook up the tweets.
went home and connected them. crossed my fingers turned everything down (gains, volume on ipod) and proceeded to turn the power on.turned the gains and volume up to find everything works 100%. i could not believe that the same system that cooked my tweets on initial start up was ok.. keep in mind i still have not found a fault in the system that would explain the first tweets being cooked, nor the amp going into protection mode (unless the missing tweets caused the amp to shut down).

thnx for the help!
now to wait on replacements from Ross..
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Old 07-19-2009, 06:52 PM
  #7  
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a simple frayed wire, a loose connection, a fault from the factory (DB?? never heard of em), an act of God?
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