external fan on rf amp

[30hrtz 10+ year member]

can running one of those small computer fans over the cooling fins of an amp help extend the life?im runnin an rf below spec ohmage,its working great but gets warm.this will have to do until i sell it and get a bigger amp.its an 08 2x50 bridged at 287 watts at 4 ohms.i got it bridged lower and it only cuts out when i get happy with the volume on the lows.can i put a fan blowing over it to help cool the outside?and will it help the inside,or can i take off the back and fan both sides?money is the issue here with family so im runnin what i got.but for a few bucks,or free from work,could a fan help the amp live longer or keep it from cutting out from time to time.thanks guys.

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[headless 10+ year member]

Yes, you can and it'll help. I would not take off the heatsink, though - it is very efficient at removing heat from the internals of the amplifier. Cool the heatsink, it will cool the internals //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I'm in a similar situation as you, and am in Florida, where trunk temps over 100f are normal all summer long. I have an old RF Punch 100DSM that i'm running a dual 2 ohm (wired to 1 ohm) bridged on....obviously well under the 4ohm bridged they rate the 100 for. It's never actually cut out though //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif But it got hot enough to fry eggs on (too hot to keep a finger on) and my 4150XXK amp pushing my fronts did cut out due to overheating on a couple of occasions...so i put a fan in between the 2 amps, pulling air off of one and over the other. It made a huge difference.

A computer fan is likely going to be pretty low current; but still, don't run it off of your remote wire directly. Your deck remote wire is only rated for extremely low amounts of current - just enough to turn on a few devices. You don't wanna fry your poor remote wire. You need to buy a relay and wire your remote wire to it, then wire your amps and fan to the relay's output - that way your deck's remote wire only needs enough current to turn on that relay.

Also, you can go up to radio shack and buy a 100mm cooling fan that spins considerably faster and pushes much more air than a 120mm computer fan....since your relay will likely be rated at something sick like 40amps at 12v, you won't need to worry about how many fans or of what type you put into your car.

A relay is basically a little box that has 3 inputs and 1 output. input 1 is it's remote/'turn on' input. It pulls a very small amount of current so can be turned on by small devices like your deck's remote wire. The next input is a 12volt power input - you'll wire some 12ga wire directly to it from your battery, or from your rear distribution +12v block. The next input is a standard ground - you'll wire a 12ga wire from the chassis of the car or from your rear distribution block or directly from your battery to that also. The last terminal on the relay is the +12V power output - you will run wire from this terminal to your amplifier's remote +turn on posts, and from this to your +12v power wire on your fan. When the relay gets 12v from your deck's remote wire on it's 'turn on' terminal, the charge from it makes it internally connect the +12v input you hooked up and the '+12v output' post that all your amps remote wires and your +12v power for your fan is wired to. Thus, the relay provides the +12v to those devices rather than your deck.

My solution was to re-wire my remote wire from the deck to the 'turn on' terminal of a relay (which they also sell at radio shack)...run 12ga power from my rear battery to the +12v terminal on the relay, then run a 12ga ground from the rear battery to the ground terminal of the relay. Last of all, i hooked up the remote wires for both amps and my fan to the 12v output of the relay. Now, the deck only needs to provide enough current on the remote wire to turn on the relay - the amps and the fan get a dedicated 12ga 12v power feed from the rear battery. The fans you will get at radio shack are louder than computer fans by a good bit...but you can't hear them in the trunk with the seats up like normal, and just one of them brought the temperatures on my amps WAY down. The 4150XXK hasn't cut out due to overheating since, even with 4 hour road trips at high volumes, and they stay barely warm to the touch UNLESS the trunk is extremely hot during the middle of the day....in which case they do still get hot...but not as hot as before.

Here's the relay you need:

http://www.radioshack.com/product/index.jsp?productId=3020762&cp=&sr=1&kw=12vdc+relay&origkw=12vdc+relay&parentPage=search

here's the fan you need

http://www.radioshack.com/product/index.jsp?productId=2102823&cp=&sr=1&kw=cooling+fan&numProdsPerPage=100&y=0&x=9&pg=1&origkw=cooling+fan&retainProdsInSession=1&parentPage=search

 

[30hrtz 10+ year member]

thanks for the very helpful answer.yup im at 1 ohm bridged also.i will do the relay like you did.Thanks again for the great descriptive answer and not flaming me for abusing my amp

 

[bamaboy 5,000+ posts]

Yes, you can and it'll help. I would not take off the heatsink, though - it is very efficient at removing heat from the internals of the amplifier. Cool the heatsink, it will cool the internals //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
I'm in a similar situation as you, and am in Florida, where trunk temps over 100f are normal all summer long. I have an old RF Punch 100DSM that i'm running a dual 2 ohm (wired to 1 ohm) bridged on....obviously well under the 4ohm bridged they rate the 100 for. It's never actually cut out though //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif But it got hot enough to fry eggs on (too hot to keep a finger on) and my 4150XXK amp pushing my fronts did cut out due to overheating on a couple of occasions...so i put a fan in between the 2 amps, pulling air off of one and over the other. It made a huge difference.

A computer fan is likely going to be pretty low current; but still, don't run it off of your remote wire directly. Your deck remote wire is only rated for extremely low amounts of current - just enough to turn on a few devices. You don't wanna fry your poor remote wire. You need to buy a relay and wire your remote wire to it, then wire your amps and fan to the relay's output - that way your deck's remote wire only needs enough current to turn on that relay.

Also, you can go up to radio shack and buy a 100mm cooling fan that spins considerably faster and pushes much more air than a 120mm computer fan....since your relay will likely be rated at something sick like 40amps at 12v, you won't need to worry about how many fans or of what type you put into your car.

A relay is basically a little box that has 3 inputs and 1 output. input 1 is it's remote/'turn on' input. It pulls a very small amount of current so can be turned on by small devices like your deck's remote wire. The next input is a 12volt power input - you'll wire some 12ga wire directly to it from your battery, or from your rear distribution +12v block. The next input is a standard ground - you'll wire a 12ga wire from the chassis of the car or from your rear distribution block or directly from your battery to that also. The last terminal on the relay is the +12V power output - you will run wire from this terminal to your amplifier's remote +turn on posts, and from this to your +12v power wire on your fan. When the relay gets 12v from your deck's remote wire on it's 'turn on' terminal, the charge from it makes it internally connect the +12v input you hooked up and the '+12v output' post that all your amps remote wires and your +12v power for your fan is wired to. Thus, the relay provides the +12v to those devices rather than your deck.

My solution was to re-wire my remote wire from the deck to the 'turn on' terminal of a relay (which they also sell at radio shack)...run 12ga power from my rear battery to the +12v terminal on the relay, then run a 12ga ground from the rear battery to the ground terminal of the relay. Last of all, i hooked up the remote wires for both amps and my fan to the 12v output of the relay. Now, the deck only needs to provide enough current on the remote wire to turn on the relay - the amps and the fan get a dedicated 12ga 12v power feed from the rear battery. The fans you will get at radio shack are louder than computer fans by a good bit...but you can't hear them in the trunk with the seats up like normal, and just one of them brought the temperatures on my amps WAY down. The 4150XXK hasn't cut out due to overheating since, even with 4 hour road trips at high volumes, and they stay barely warm to the touch UNLESS the trunk is extremely hot during the middle of the day....in which case they do still get hot...but not as hot as before.

Here's the relay you need:

http://www.radioshack.com/product/index.jsp?productId=3020762&cp=&sr=1&kw=12vdc+relay&origkw=12vdc+relay&parentPage=search

here's the fan you need

http://www.radioshack.com/product/index.jsp?productId=2102823&cp=&sr=1&kw=cooling+fan&numProdsPerPage=100&y=0&x=9&pg=1&origkw=cooling+fan&retainProdsInSession=1&parentPage=search

nice post man

just be aware a fan might not fix the problem since you have it wired so low, it will help though

 

[benchambers80]

relay that bish

 

[IDSkoT 5,000+ posts]

Great post, headless. I've been thinking about doing this but I wasn't sure how well it'd work.

Did you make some sort of mounting post for the fans? You mind taking a picture of it for us to see?

 

[headless 10+ year member]

thx guys

My camera is broken, so i can't take a picture of the mounting. But i can mspaint it //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif The other benefit of using the fan that has a metal frame from radio shack instead of a computer fan is the mounting differences. Computer case fans are meant to be screwed in flush to blow air through whatever they are mounted to...we want to have air blown over something horizontally rather than down on it directly like a case fan normally does. The 'hobby fan' you get at radio shack has flanges with holes that allow you to screw the fan down directly to your amp rack/board at a 90 degree angle to the board that case fans don't have...example pic below