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Old 07-31-2020, 09:40 PM   #1
LeedomtoFreedom
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Default Amplifier cooling = speakers buzzing

Basically I've got 2 amps tucked in the passenger rear well. After a while they get very hot, so I've decided to add a cooling fan. It's just a 12v DC computer fan. plenty of airflow.

The question is that when I have the fan on it causes the speakers to buzz pretty loudly. I'm guessing it's feedback in the system. Originally I had the fan hooked to the 12v signal wire on the amp which caused the buzz. Switched to a direct 12v switched circuit to the front from a spare fuse box, still the same buzz.

I don't totally understand the workings of amps and radio noise and all this. Just looking for some leads or any light on this situation.
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Old 07-31-2020, 09:43 PM   #2
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It is a ground problem. Play with ground locations until it goes away, I would start with grounding it to where the amp is grounded. You can use the signal wire if it is large enough, I would use 14 gauge or so.
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Old 07-31-2020, 10:55 PM   #3
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I've thought about doing something like that. My amp is in the compartment under the floor of the wagon. Perhaps a computer fan?
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Old 07-31-2020, 11:23 PM   #4
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Use 2 fans, one points in, one exhausts the heat
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Old 08-01-2020, 12:34 PM   #5
LeedomtoFreedom
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I'll have a look at grounds

I picked up a 120mm 3 wire fan for a computer. Dead cheap off eBay. I'm pretty sure 120 is fairly standard for computers.
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Old 08-06-2020, 01:41 PM   #6
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If anyone cares. I'm pretty sure it's coming from crosstalk not grounding. Please hold for results.
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Old 08-06-2020, 01:50 PM   #7
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Quote:
Originally Posted by LeedomtoFreedom View Post
It's just a 12v DC computer fan.
Which fan specifically? computer fans are electrically noisy, more so with the cheap ones. Most of them are either controlled with an external PWM signal, or can vary their own speed using an internal thermistor. Have you tried a different fan?
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Old 08-06-2020, 09:41 PM   #8
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I have none other available right now. I've lessened it but still haven't gotten rid of it. Going to continue looking for info.
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