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amp cooling problem, not like the other one

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Old Apr 23, 2006 | 07:44 PM
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amp cooling problem, not like the other one

I have a 6 or 7 year old jensen 200 W amp 2 ch. I dont know what ohm it is stable at but i have it bridged. It has no fans or openings, it is all solid everywhere around. It heats up fast and burnt myself on it. It also shuts off when turning it up too loud when warmed up. What way can I keep it cool or mount it where can stay cool. thanks for any advice.
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Old Apr 23, 2006 | 08:10 PM
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Car: 88 camaro, black, T-tops
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first, find out what kind of ohm load your speakers are and get back to us.
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Old Apr 23, 2006 | 08:15 PM
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how can I find out what ohm load its puttin out?
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Old Apr 23, 2006 | 08:26 PM
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1: pull the speaker/sub and look on the back of each one.
2: at the final set of wires connect a ohm meter or multi meter.

ohm loads on speakers are as important to a car stereo as a exhaust is on a motor.
Right amount of restriction= good. Wrong amount of restriction=bad.
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Old Apr 24, 2006 | 07:15 PM
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i checked it and it is a little over 4 ohms.
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Old Apr 24, 2006 | 09:29 PM
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Originally Posted by lowgas&rubber
i checked it and it is a little over 4 ohms.
4 ohms per coil, 4 ohms final?

To put this simply: how many subs are you running? How many coils do they have? What’s the resistance of one coil?

If your final load is 4 ohms you should be fine assuming the amp is bridgeable to 4 ohms. I would be surprised if it's not.
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Old Apr 24, 2006 | 09:31 PM
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i am running 1 sub with dual voice coil
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Old Apr 24, 2006 | 09:59 PM
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2 ohm coils or 4 ohm coils? Just trying to make sure we're saying the same thing when you say 4 ohms
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Old Apr 25, 2006 | 08:48 PM
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4 ohm coils
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Old Apr 25, 2006 | 09:27 PM
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Originally Posted by lowgas&rubber
4 ohm coils
So your wiring choices are 2 or 8 ohms, 2 ohms being the preferable choice. Post the model # on the amp and someone will be able to turn up whether or not it's 2 ohm stable.
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Old Apr 26, 2006 | 04:27 PM
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yeah if its a jensen amp i don't think its capable of 2ohm mono bridged (aka 1ohm) operation. Hence your overheating problem.
4 and 4 parallel = 2ohms, bridge that and you get 1 ohm.
4 and 4 in series = 8ohms, bridge that and you get 4 ohms.
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Old Apr 26, 2006 | 09:25 PM
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From: Readington, NJ
Car: 88 GTA
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Axle/Gears: 9 bolt w/ 3.73
Originally Posted by lockchad
yeah if its a jensen amp i don't think its capable of 2ohm mono bridged (aka 1ohm) operation. Hence your overheating problem.
4 and 4 parallel = 2ohms, bridge that and you get 1 ohm.
4 and 4 in series = 8ohms, bridge that and you get 4 ohms.
I'm going to call your post confusing for the average user. If you're confused, refer to this thread and scroll about 1/2 way down.

No, the speakers impedance doesn't change when an amplifier is bridged.

BUT

When a two channel amp is bridged to a 4 ohm speaker, it puts the same load on the amplifier as running two 2 ohm speakers in stereo. This is why most class AB amplifiers are 2ohm stereo / 4ohm mono stable. This is also why an amp would put out 50 watts x2 @ 4ohm, 90 watts x2 @ 2ohm and 180 watts x1 @ 4ohm.

Here's a little more reading

Bridgeable Amplifiers
So true, you're bridging the amp down to a 1 ohm load with two 4 ohm loads in parallel but most amp manufacturers will say that their amp is 2 ohms stable.

This is the way most people understand it so I figured I would post it.
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Old May 11, 2006 | 11:33 AM
  #13  
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Does your sub have two sets of speaker terminals? wouldn't that give him 4 ohms per channel?
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