# Do cross flow fans work better than installing a regular fan to keep amp cooler



## coomaster1 (Jul 22, 2010)

Hi, I was wondering if anyone has used what is called a cross flow fan to help keep their amplifier temperature down. If so how did it work for you,Was the temperature a lot cooler. It looks like 3 companies make them.One by Pac, one by stinger,and the other by xscorpion. All seem to be 8 inches. How do these exactly work. Do you just install it by your heat sink,or does it install in the amp.Does it wire in with your remote turn on and off wire so it isn't constantly running. My other question is: Wouldn't it be just as good,if not better to lift the amp up about an inch or two off of where it is mounted,and take the bottom plate off the amp,so heat will easily be able to escape out the bottom of the amplifier,While using a regular 4 inch fan mounted at one end of the open bottom,forcing air flow up,to the side ,and then out the other side of the bottom of the amp. Also this would be quick to do,and you won't half to hack up your amp,whatsoever. Thanks


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## DDfusion (Apr 23, 2015)

Why do you think you need fans? If the amps are not going thermal the heat sinks are doing their job. Normally if it's a good amp and didn't come with a fan they are not needed


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## coomaster1 (Jul 22, 2010)

Hi, Even though they are not going into thermal protection mode,I would still like to keep them cooler when I am pushing the amplifiers hard for extended periods of time in the summer months, so I can listen longer.My amps are oldschool class AB alpine 3544 amps. When you go up to the next model up.The alpine 3545.It has 2 built in fans in it. I want to keep things cooler regardless of going into thermal protection mode or not .


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## drop1 (Jul 26, 2015)

In the past I just used 2 computer fans. One on either side of the Amps in a push/pull configuration. One blows across the amps one pulls that air and blows it out the other side. If you get the right fans they are super quiet as well. You probably don't need fans at all but if it's your thing go for it.

Also I just tapped into the remote wire the grounded the other wire. If the amps had power the fans were running. Easy peasy.


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## Victor_inox (Apr 27, 2012)

I`m all for forced air cooling, thermal exchange is about 20 times better than convection alone. right fans virtually silent and every component will serve longer when cool.
Crossflow fans even quieter usually. go for it.


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## coomaster1 (Jul 22, 2010)

Hi,Will my idea of lifting the amp up off the floor an inch or two,and taking off the bottom plate,and blowing air from the bottom up with a fan work to cool the amp properly ,so I don't half to cut up the amp in any way. The computer fans seem like a good idea, but they will not be 12 volt. Is there a good place to buy a fan that is 12 volt,fairly silent,and is a low amp fan,so as to not draw too many amps. I see some fans are less than one amp,and some are way up at 12 amps.I would like to keep the amp draw low since,I am drawing a lot of amps already.Also how do you tell by looking at the picture of the fan ,if it blows a lot of air to be considered a good cooling fan.It looks like I can fit a 4 inch fan,mabe 5 inch max on each side when I remove the plate. Do you guys have a place that sells a fan with the requirements that I have discussed here.Thanks for your help so far.


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## Victor_inox (Apr 27, 2012)

Computer fans are 12 volt, all of them except laptops use 5V.


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## Victor_inox (Apr 27, 2012)

fans measured in millimeters please get use to it. common sizes 40,50,60, 80, 90mm.
ebay would your cheapest place for computer fans.
How about you make a picture of proposed fan location and we1ll go from there.


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## drop1 (Jul 26, 2015)

Lifting your amps is not a bad idea. Taking the plates off is over kill. Seriously unless you are clipping them they are already fine, adding fans to cycle air across the fins is more than enough.
Taking your plates off is going to turn your amp into a dust factory . Ever look inside a computer after a few months? It's terrible.


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## subterFUSE (Sep 21, 2009)

BlackNoise Pro fans.

Amazon.com



That is all I can offer.


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## coomaster1 (Jul 22, 2010)

I have no digital camera to take any pictures. After talking with you guys ,I will leave the bottom cover on. I was fooled into thinking since the computer plugs into the wall outlet,that computer fans were a different voltage than 12 volt. Thanks for correcting me on this. This will make looking for a fan that much easier. Do all fans flow about the same air flow.or is there a minimum cubic foot per minute number I should be getting. When looking at 12 volt fans.How many wires should it have.One for positive,one for negative,and is there another wire on the fan ,so you can hook it up to your remote on wire on your amp so the fan turns on and off when the amp turns on and off.


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## Victor_inox (Apr 27, 2012)

3rd wire is tach reading not remote

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## Victor_inox (Apr 27, 2012)

There fans with 4 wires but that is rpm control wire

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## subterFUSE (Sep 21, 2009)

coomaster1 said:


> I have no digital camera to take any pictures. After talking with you guys ,I will leave the bottom cover on. I was fooled into thinking since the computer plugs into the wall outlet,that computer fans were a different voltage than 12 volt. Thanks for correcting me on this. This will make looking for a fan that much easier. Do all fans flow about the same air flow.or is there a minimum cubic foot per minute number I should be getting. When looking at 12 volt fans.How many wires should it have.One for positive,one for negative,and is there another wire on the fan ,so you can hook it up to your remote on wire on your amp so the fan turns on and off when the amp turns on and off.



BlackNoise Pro.

Amazon.com



search them. all answers will become apparent.


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## gckless (Oct 11, 2012)

Taking the covers off most doesn't do a whole lot. Only if you have smaller heatsinks on individual components. Otherwise, all the heat exchange takes place on the MOSFET heatsink, which is the case. Focus air flow wherever there is the most surface area. Heat exchange is all about surface area.


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## kyheng (Jan 31, 2007)

In electronic stuffs, heat generation is from the components it self and not from the circuit board. If really want to use fan cooling, better put more effort on cooling the components.
Exposing the bottom circuit board won't do much good.
Also, with fan cooling, you need to clean the fans regularly.


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## kustomkaraudio (Jun 20, 2009)

subterFUSE said:


> BlackNoise Pro.
> 
> Amazon.com
> 
> ...


X2 !!

The Black Noise fans are the best. The most quiet fans on the market. I can't remember if we put 6 or 8 in Gary's Mercedes, but you can't even tell they are running, very impressive.


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## coomaster1 (Jul 22, 2010)

Hi,It sounds like the black noise pro fans are quiet, quality fans,I will order them. If they are good enough for you guys,they are definitely good enough for me. Does it just come in one size or are there lots of sizes. After checking I see a fan that comes up on amazon that says Noiseblocker NB-black silent pro PK 3 140mm x 25mm ultra quiet fan-1700 rpm with 5 customer reviews with all being 5 stars. It is not called black noise pro. Have they changed the name.This is what comes up when I type in black noise pro.It sounds like the best of the series,am I correct on this My final questions before I order and get started. Do those fans come with their own remote wire so the fan doesn't continually run.If not, how do you hook it up to just come on when the amp comes on. Thanks again


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## subterFUSE (Sep 21, 2009)

Black noise comes in all sorts of sizes. From 40mm to 60 to 120, etc... Look up their product website for details.

In my car, the sub amp has a fan remote wire trigger with internal thermometer. We're using that as the trigger.

Frankly, these fans are so damned silent that you can just leave them running all the time. You'll never hear them.

Sent from my iPhone using Tapatalk


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## coomaster1 (Jul 22, 2010)

When I looked up the black noise pro fans it comes up as noise blocker. Is this the same fan as the black noise fans.If so the company has changed the name from black noise to noise blocker. The biggest I see is the 140mm x 140mm x 25mm. I just want you to confirm we are talking about he same company. Also my alpine 3544 amps don't have any remote wire trigger.Is there a way to hook it up to come on when just the amp comes on.If not , Do I just hook the positive wire on the fan to the positive terminal on my amp,and the negative wire on the fan to the negative terminal on the amp.


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## subterFUSE (Sep 21, 2009)

Blacknoise.com


Sent from my iPhone using Tapatalk


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## coomaster1 (Jul 22, 2010)

It looks like they are the same company.Thanks for all your help.as well as everyone that participated in this thread . Enjoy the rest of your evening.


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## kyheng (Jan 31, 2007)

You may use the amp's remote wire to trigger a relay to start the fans.


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## coomaster1 (Jul 22, 2010)

Thanks for verifying that I can definitely use the amps remote wire to trigger a relay to start the fan. Does the relay you speak of come with the fan.Or do you just mean that when I hook up my fan to the amp, I just hook up the fan power wire to the positive on the amp,and the negative wire on the fan to the negative on the amp,and the third wire on the fan goes to the remote on terminal on the amp or is it different than that. Thanks


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## Victor_inox (Apr 27, 2012)

See posts 12 an 13. look at the fan you`ll be using if it`s says something like 0.1A or less you can hook it up directly to the remote wire no relay needed.
remote circuit made for 0.3A current sometimes more than that. I just checked fans I have 0.07 to 0.13 for all of them, you can use at least 2 fans with no problem to remote circuit of your HU.


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## kyheng (Jan 31, 2007)

coomaster1 said:


> Thanks for verifying that I can definitely use the amps remote wire to trigger a relay to start the fan. Does the relay you speak of come with the fan.Or do you just mean that when I hook up my fan to the amp, I just hook up the fan power wire to the positive on the amp,and the negative wire on the fan to the negative on the amp,and the third wire on the fan goes to the remote on terminal on the amp or is it different than that. Thanks


Like Victor said, it depends how many fans you are using. If just 1-2 fans, remote as power to the fan are more than enough, but if you are using more, then getting a relay would be a better option.
A relay can be a SPDT or SPST type, put a 10A fuse will be enough.


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## coomaster1 (Jul 22, 2010)

Hi, You guys definitely answered my questions about the remote on issue. I will only be using one fan per amplifier, so it sounds like I will be able to simply use the remote on wire. I was planning on using those blacknoise fans people here recommended. I notice they spin at 1700 rpms. Will I be forced to run the fans at that speed,since I have no way of slowing them down like a computer does,and will it do any damage to the fans if they run at the maximum 1700 rpms.


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## cajunner (Apr 13, 2007)

I would run the fans off of the car's ignition wire that feeds the radio and accessories in the fuse panel, before I'd run them off of ANY remote turn-on lead from a deck, including the power antenna lead, and the amp remote.

I know it means that the fans run when the vehicle is on, and that turning off the deck doesn't turn off the fans, but that's no issue to me.

I wouldn't want to bring up the deck's remote relay circuit in amp draw until it was maxed out, or even put any kind of additional circuit in there without using a relay.

Use the circuits as they were designed, and if you have a turn-on from an amp that draws enough current to reach half of the rating on the deck, use a relay.

just an opinion..


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## Theslaking (Oct 8, 2013)

cajunner said:


> I wouldn't want to bring up the deck's remote relay circuit in amp draw until it was maxed out, or even put any kind of additional circuit in there without using a relay.
> 
> Use the circuits as they were designed, and if you have a turn-on from an amp that draws enough current to reach half of the rating on the deck, use a relay.
> 
> just an opinion..


I agree. You can get a cheap relay for just a few dollars from any box store. Or, just order one with your fans.


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## coomaster1 (Jul 22, 2010)

When looking for a relay for the blacknoise pro 140mm x 140mm fan. What is the relay called exactly ,and is there a relay that you guys recommend that is a quality relay more suited to the fan I am talking about. I,ve heard of a relay in the engine compartment,but not sure at all what is needed here,Thanks


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## Victor_inox (Apr 27, 2012)

I can sell you fans and relay if you believe those guys that your remote wire has not enough juice to supply couple of 0.1A fans. I actually like caj idea running fans out of accessory wire, you turn you ignition your fans started moving air. 1700rpm is nothing to worry about. If you worry about longevity insert 200 Ohm resistor in series and it will lower rpm. and airflow of course.


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## Beckerson1 (Jul 3, 2012)

I just grab my relays off amazon really. There the 5 pin SPDT type iirc. 40A. Friendly on the budget and usually just grab a 5 pack with harnesses.

Way overkill but work just fine for fans, ect...


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## cajunner (Apr 13, 2007)

Victor_inox said:


> I can sell you fans and relay if you believe those guys that your remote wire has not enough juice to supply couple of 0.1A fans. I actually like caj idea running fans out of accessory wire, you turn you ignition your fans started moving air. 1700rpm is nothing to worry about. If you worry about longevity insert 200 Ohm resistor in series and it will lower rpm. and airflow of course.


added benefit of cooling the amps off while not listening to the stereo, just driving.

detractor is the fans are always on making dust bunny build-up removal, more often.

I don't believe car stereo manufacturers designed their decks to drive outboard fans off the turn-on circuits.

Much like I don't believe car manufacturers designed their electrical systems around 2KW RMS system draw in the audio.

It's more insurance than anything, I'm sure a 12V .24 amp fan may do rated, but if you're at 14.4V system voltage and the deck is supplying a circuit that scales with the system voltage, the draw on that fan could be .37 amps, and dangerously high when combined with the .15 amps of the amplifier turn on circuit engaged.

and just one amp!


add any DSP to it and you're over the max on most decks.


there's specialty circuits just for this, I'd get one of those special fan controllers that have the relay built in, and computerized control over the amp temperatures so I could get that extra level of assurance the heat dissipation provided by the fans were enough, and if not I'd return to the system design by reducing current flow through the amps by using higher impedances.


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## gckless (Oct 11, 2012)

I use the HU's remote turn-on for sense on a relay. That relay powers all my amps, fans, meters, etc. Then from that relay, in between the fans, I run a switch. That way, I can either have them totally off, or on when the amps are on.


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## Victor_inox (Apr 27, 2012)

cajunner said:


> added benefit of cooling the amps off while not listening to the stereo, just driving.
> 
> detractor is the fans are always on making dust bunny build-up removal, more often.
> 
> ...


Voltage raises current drops, yo got it backwards dude!


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## cajunner (Apr 13, 2007)

Victor_inox said:


> Voltage raises current drops, yo got it backwards dude!


how so?

if the motor is a static load and it draws .24 amps at 12V, then like a light bulb will glow brighter, the fan will turn harder when supplied more voltage?

if the voltage is raised, the amount of current remains the same? I don't know...

seems to me that a fan that was running at 12V is limited to the .24 amps of current, but if you have 14.4V available, the current will also increase, hmmm...


I think you may have got me there, Victor!

something I'm relating from amplifier circuits to motor loads, maybe...

but if that's wrong, then I'm sticking with my original thought which was that fans shouldn't be run off of deck turn-on circuits even if they present a minimal load because the turn-on circuit as far as I know, was not meant to supply a load with actual current flow, only as an electronic switch...


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## Victor_inox (Apr 27, 2012)

Let me help you here. 
there is no current limiter on light bulb. 
Why amplifiers often burn when voltage drops? some of them, without proper protection circuit?
And you are incorrect, remote circuit is not switch signal it supplies constant current to the load. If only remote switch in amps would have momentary switch as you said life would be so much easier in our hobby. If you take 20 seconds with multimeter to any car amplifier you have I guarantee that what you`ll find out. 
Following my drift?


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## seafish (Aug 1, 2012)

Don't need a multimeter…just do the math--

Amps x Volts = Watts

As volts increase, amperage will always decrease given a steady load.


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## cajunner (Apr 13, 2007)

yeah, I think so.

still, I remember a lot of trouble from back in the day where I had multiple amps, 2 electronic crossovers, an equalizer, etc. all running off a deck's turn-on circuit and it was explained to me then, that depending on the amount of draw necessary, you could easily damage the deck just doing what it appeared was possible.

the need for relays and understanding why you need them was some of that 'shop secret sauce' that you paid extra for, and usually came with the purchase of some little relay box the shop built for a big markup...

now you can go on the internet and not only buy a relay designed for soft start, and no pop turn-off you can buy it from China and have them deliver it to your door.


no assembly required, haha...

but even if I'm wrong about the amount of current flow required to turn fans compared to turn amps on, I still think it's a good idea to take the bulk of any parasitic losses through the deck away, and the turn-on circuit overloading is one of them..


the Alpine decks from a few years back had a black-out feature, because they said the sound quality improved when the internal power supply didn't have to run the fluorescent display...

and that's kind of where I get the idea from.


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## Victor_inox (Apr 27, 2012)

OK how about that, if two computer fans blow his remote circuit I`ll fix it on my dime and pay shipping both ways? any computer fans commercially available today. 
Yes assembled relay circuit cost about 5 bucks on amazon but why bother, I certainly wouldn`t.
Yes HT receivers still have that turn off screen feature calling it "pure", I have no confirmed facts that it will lover any appreciable amount of current to ease PSU load.


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## cajunner (Apr 13, 2007)

Victor_inox said:


> OK how about that, if two computer fans blow his remote circuit I`ll fix it on my dime and pay shipping both ways? any computer fans commercially available today.
> Yes assembled relay circuit cost about 5 bucks on amazon but why bother, I certainly wouldn`t.
> Yes HT receivers still have that turn off screen feature calling it "pure", I have no confirmed facts that it will lover any appreciable amount of current to ease PSU load.


well, I don't need any assurances on my end...

haha..

but if we're splitting hairs I'd go for the relay.

the idea that we just slap fans onto a turn-on circuit as 'best practices' or advice is a little troublesome on my end, but I don't have the in-depth understanding about these things like you, I believe marketing spiels and sometimes I try to minimize the amount of install variables that differ from the installation sheet...

but if he wants to run his amps' fans on the turn-on juice, it's perhaps roll of dice?


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## Victor_inox (Apr 27, 2012)

Ohhh come on, everything in life roll of dice. You start ripping off that perfectly fine stock 17speakers system and that`s what you doing. Intentionally I might add.
ActuallI like solution you offered earlier in the thread to run accessory wire to the trunk, much more reliable than remote wire and only limited by the fuse in the box.


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## coomaster1 (Jul 22, 2010)

Hi, Sorry for the late reply back to everyone.I'm just getting back in. If you guys don't think there will be any harm done to the fan running all the time for 2-3 hours at a time when my car is running,or to anything will happen to the electrical in the car. I think I will just run the fans constantly, since I always turn the stereo on before I even back the car out to drive.Though I play it pretty low at first to make sure everything is warmed up. If I just run the fan constantly ,Will this mean I don't need to worry about the relay or remote on wire at all.And just hook the fan directly to the positive and negative terminal on the amp? Also if I can get the fan inside the amp between the components that are getting hot,and the heat sink.Is this the very best place to put the fan to get the best cooling for the amplifier.My logic says if you are blowing air directly on the parts that are getting hot,you can't get any better place to put the fan,But what do I know.


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## drop1 (Jul 26, 2015)

No. I mentioned the remote wire because it gets power when the radio comes on. The positive and negative at the amps have constant power meaning your fans would never shut off . You can hook them up there but you will need to put them on a switch. The remote wire does not get constant power. It gets activated once the radio comes on and if you don't wanna run a relay or switch it's the easiest option.


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## coomaster1 (Jul 22, 2010)

I thought the amplifiers didn't get any power at all when the car ignition is off. That's why I figured I would hook the fan to the positive and negative on the amp ,So when I turn on the car there would then,and only then be power to the amps ,and fan.Or are you saying, that even when my ignition is off .There is still live power going to the positive and negative on the amplifiers.


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## drop1 (Jul 26, 2015)

No sir. There should be nothing between your battery and the amp on the positive wire except a fuse or distribution block. That line is always hot. The ground Is tied into the frame of the vehicle which is also directly connected to the battery. 

The remote wires whole purpose is to activate a switch , relay or whatever inside the amp to completely the circut. Think of a light switch on the wall. It always has power. The remote wire is basically the finger you use to flip the switch .


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## coomaster1 (Jul 22, 2010)

Ok I see now.Thanks for correcting me on that. Should I put the fan in between the components that get hot in the amp and the heat sink to get the best cooling for the amp. If so I think I'm ready to order the fans. Thanks


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## Victor_inox (Apr 27, 2012)

While you are at that buy yourself infrared thermometer like this








Measure hottest part of the amp first.
If it's less then 140 don't bother.if more then blow air on that. 

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## coomaster1 (Jul 22, 2010)

That's a sweet looking thermometer,When you have tested amplifiers for how hot they are getting,Where did you find was the hottest place the amplifier was producing heat from,and if it is higher than 140 ,do you recommend me placing the fan where I have described in my earlier posts.


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## Victor_inox (Apr 27, 2012)

You can get one at harbor freight for cheap.
Many amps get too hot to touch and that is normal.in fact 95F is too hot but for components inside it's nothing.caps good to 105C that is more then 230F.mosfets to 180 and that is about 400F.
As of dust bunnies I wouldn't worry about that unless you have tight spots like inside if a computer. 
See you cig lighter is not hot until you put the key in acc position. Best way to wire your fans.you don't want them to run all the time.

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## coomaster1 (Jul 22, 2010)

Thanks for all the specs on amp heat and components.I didn't know they could get that hot on a regular basis without doing damage to the amplifier. I'm going to check out one of those thermometers. Thanks for all your help.


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## kyheng (Jan 31, 2007)

Another way to keep amp cool is don't run lower impedance. I'm running 8 ohm woofer on my sub amp.


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