JVC DOA

JVC DOA

PostBy: Dann757 On: Sat Dec 18, 2010 4:38 am

My car stereo I got in March 2010 just croaked. NO SOUND. 9 months life? Maybe that's why it was on clearance?
JVC KDR200- got it on clearance at Best Buy. I gotta call tomorrow and see if there is any warranty option. It's suppposed to be 4 x 50watts, so I'm hoping the speakers I rigged into the doors didn't wreck the unit, (ceiling speakers from somebody's mansion) uh oh, the same thing happened to the last stereo I had in the Ranger. I hope I'm not destroying stereos with these house speakers. Also wondering if there's some wiring anomaly that is causing these problems. I don't think it's a bad ground.
Dann757
 

Re: JVC DOA

PostBy: europachris On: Sat Dec 18, 2010 10:55 am

With solid state equipment, you usually get more power output with lower impedance speakers, i.e. 50 watts into 8 ohms and 75 watts into 4 ohms. That is usually not a problem unless you have speakers that are really low impedance and also really inefficient, causing you to have to really crank up the volume to get a decent level of sound. This will stress and overheat the output transistors and eventually they will fail. Also, shorting the output can be quick death to transistors. I've never had any problems with car decks (stock or aftermarket) but I really don't turn it up loud where I'd ever be at risk of blowing something out.

I don't mess with solid state much - I prefer building tube audio equipment which has the opposite problem - running with NO speakers attached can be very damaging. But, it's a lot more work trying to build mobile tube car amplification because you have to generate 350 to 400VDC from a 12V supply which takes a lot of solid state electronics, kinda defeating the whole purpose in the first place..... 8-)
europachris
 
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Re: JVC DOA

PostBy: Poconoeagle On: Sat Dec 18, 2010 11:10 am

yes the home audio speakers almost always have different impedence than auto.

When I put the D-9 Cerwin Vega's in the rear of my custom van i ran them thru a separate amp as well as a home built from radio shack crossover network.

the transistors take a hit if its not matched..
Poconoeagle
 
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Re: JVC DOA

PostBy: SMITTY On: Sat Dec 18, 2010 11:27 am

Yeah I think all car stuff is 4 ohm. Been decades since I've messed with stereos, but that part I remember. Can't tell you for certain if that's the problem ... although I know more resistance = more heat ... :gee:
SMITTY
 
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Re: JVC DOA

PostBy: Dann757 On: Sat Dec 18, 2010 12:54 pm

Thanks guys.
I never beat the unit, and sound was always adequate. Never really went over 25 on a 50 volume scale. I have all original paperwork and packaging. Of course, I called JVC and it's comical how many times you have to run around before you get any human to talk to. I just talked to some dude in Texas, after pressing numbers for 5 minutes, he has to have the serial number :shock: .
gotta go pull the deck and find it.

I called Best Buy- three customers in front of me before I talk to anybody- not a good season to get help there. All this for a $75 deck.

I have an old buddy that was into vintage tube stuff, that's really hardcore if you're running it in your jalopy.

Only clue I have is when I turn on the ignition, I get a little audible bump from the speakers, which tells me there is good connections to the speakers at least.

Plus the frigid cold might have something to do with it.
Dann757
 

Re: JVC DOA

PostBy: 009to090 On: Sat Dec 18, 2010 5:44 pm

Dann757 wrote: I just talked to some dude in Texas, after pressing numbers for 5 minutes, he has to have the serial number :shock: .
gotta go pull the deck and find it.

Dan, the original box should have the S/N on the barcode label. No need to pull the unit out of the dash.
009to090
 
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Re: JVC DOA

PostBy: Dann757 On: Sat Dec 18, 2010 7:35 pm

DVC500 at last wrote:Dan, the original box should have the S/N on the barcode label. No need to pull the unit out of the dash.


Duhhh. Thanks, Chris.

Too late, I ripped the unit out of the Ranger a la Smitty style. I mean ripped it out. :cry: Threw it out. I'll redo everything after the holiday madness.
Dann757