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You are correct. Back to front is contraventional. It'd be pretty involved to turn the air flow around on a Behringer. Easiest way might be with another fan inside...but meh.

Are other pro amps back to front? Is that a pro gear thing or a Behringer thing?
just reverse fan direction... easy enough to monitor temps
 

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Think of a cup of coffee...you cool it off by blowing. The opposite just won't work.

Right, when sucking the air can be drawn from all around and the average velocity drops off quickly with distance, whereas when blowing the momentum keeps the airflow directional for a far greater distance.

When trying to cool something, change from blowing to sucking at your peril.
 

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Think of a cup of coffee...you cool it off by blowing. The opposite just won't work.

Right, when sucking the air can be drawn from all around and the average velocity drops off quickly with distance, whereas when blowing the momentum keeps the airflow directional for a far greater distance.

When trying to cool something, change from blowing to sucking at your peril.
That does not apply here at all. The analogy is typically blowing out a candle vs sucking out a candle. However that only applies to a fan in free air. Free air being the key.

In a ducted system it makes no difference if the fan is in push or pull configuration. CFM through the duct is CFM through the duct, and the amplifier case essentially acts as a duct either being blown into (supply configuration) or having air pulled through it (exhaust configuration).

Think of a laboratory fume good for example. It is connected to an exhaust fan which negatively pressurized the duct and the fume hood. That means air is pulled through the opening on the fume hood and all that CFM is pulled out of the exhaust. The amplifier case is a closed box (with minimal leakage) and the openings are in the front. If the exhaust fan is blowing out X amount of CFM it has to come from the grill in the front, move over the circuit board, and come out the back exhaust.
 

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Discussion Starter #65
That does not apply here at all. The analogy is typically blowing out a candle vs sucking out a candle. However that only applies to a fan in free air. Free air being the key.

In a ducted system it makes no difference if the fan is in push or pull configuration. CFM through the duct is CFM through the duct, and the amplifier case essentially acts as a duct either being blown into (supply configuration) or having air pulled through it (exhaust configuration).

Think of a laboratory fume good for example. It is connected to an exhaust fan which negatively pressurized the duct and the fume hood. That means air is pulled through the opening on the fume hood and all that CFM is pulled out of the exhaust. The amplifier case is a closed box (with minimal leakage) and the openings are in the front. If the exhaust fan is blowing out X amount of CFM it has to come from the grill in the front, move over the circuit board, and come out the back exhaust.
I'm not at all convinced. I'll never turn my fan(s) around. You (I) don't want air coming to the fan from just anywhere inside the case to the fan. I want to blow as much of the concentrated CFM directly on the components that need to be cooled. There is flimsy plastic sheet ducting within the case to intended to help do just that. It would also help direct reversed air flow too but it would not be nearly as effective.

Go back to the hot coffee scenario again. That is open air flow. You could even inhale air from very near the top of the coffee by tilting the cup. Still, if you want to cool the coffee, you blow on it.
 

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Go back to the hot coffee scenario again. That is open air flow. You could even inhale air from very near the top of the coffee by tilting the cup. Still, if you want to cool the coffee, you blow on it.
That’s my exact point. We’re not dealing with an open air flow and that’s why that analogy doesn’t work with what’s actually going on. The amplifier case is an enclosure. If you mount the fans backwards so they are exhausting air, air has to be “made up” from somewhere, and that’s going to be from the front of the case where the openings are. So air will flow from the front of the case through the case and out the back all while passing over the circuit board. It’s not going to short circuit the air somewhere and not pass over the board.

If you removed the top of the case and mounted the fans backwards, that’s when the analogy of the hot coffee (or my candle) would apply, but that’s not what we’re talking about here.
 

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In a ducted system it makes no difference if the fan is in push or pull configuration.

True enough if there are ducts; I missed that that is the case here.

But is it?

I have nu3000 and nu6000 and they don't have any to speak of.
 

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My 3000’s have shrouds over the amp area.

I remember seeing the older NU6000’s with the same.


Sent from my iPhone using Tapatalk
 

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My 3000’s have shrouds over the amp area.

I remember seeing the older NU6000’s with the same.

A shroud isn't going to help much unless it's extended all the way to the fan, at which point it's a duct.

I forget what it looks like and didn't want to spend more than the couple of minutes I did looking for pics.
 

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When the fan is blowing into the case the air exits proportionally from any openings in the case. With a proper case design that has correctly located exit openings this will direct the proper amount of air over the components that require cooling. If you reverse the fan, why wouldn't it draw air in equal proportions from those same openings in the case in the same volumes over the same components?
 

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Discussion Starter #72
When the fan is blowing into the case the air exits proportionally from any openings in the case. With a proper case design that has correctly located exit openings this will direct the proper amount of air over the components that require cooling. If you reverse the fan, why wouldn't it draw air in equal proportions from those same openings in the case in the same volumes over the same components?
I agree. Correct airflow direction can be done and has by other brands. For whatever reason, most likely appearance, efficiency (of the unit itself not including rack mounting with other gear), and cost, Behringer chose reverse air flow and designed for that. The current design puts the fan as close to the heatsink as it can be without redesigning the board.
 

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When the fan is blowing into the case the air exits proportionally from any openings in the case. With a proper case design that has correctly located exit openings this will direct the proper amount of air over the components that require cooling. If you reverse the fan, why wouldn't it draw air in equal proportions from those same openings in the case in the same volumes over the same components?
The best thing to do would be to have a fan providing positive pressure in front and a fan providing negative pressure in the back. I know some lower end servers, who cut corners by providing less peripherals prefer to provide only the negative pressure but a lot of cases are engineered to have many zones. With smaller cases such as a 1U or 2U you can create universal air direction with just negative pressure. In the case of the beheringer with home use and not DJ'ing the providing cooling is over kill.
 

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Discussion Starter #74 (Edited)
The best thing to do would be to have a fan providing positive pressure in front and a fan providing negative pressure in the back. I know some lower end servers, who cut corners by providing less peripherals prefer to provide only the negative pressure but a lot of cases are engineered to have many zones. With smaller cases such as a 1U or 2U you can create universal air direction with just negative pressure. In the case of the beheringer with home use and not DJ'ing the providing cooling is over kill.
Comparing a server case to an amplifier case is not a 1 to 1 comparison. Computers have a CPU cooler within that pushes (and sometimes pulls too) the air directly thru the heatsink. You are just trying to get air thru the case so the CPU fan (and GPU and PS) can have cool air to intake and concentrate on the heatsink(s).
 

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Comparing a server case to an amplifier case is not a 1 to 1 comparison. Computers have a CPU cooler within that pushes (and sometimes pulls too) the air directly thru the heatsink. You are just trying to get air thru the case so the CPU fan (and GPU and PS) can have cool air to intake and concentrate on the heatsink(s).
1U and 2U is very similar to what you'd find in a low end amplifier like the one we are talking about. Most of the 1U's I worked on were just open shells with a motherboard and no peripherals, cooling requirements being laughable. Often times with a 2U, since those are popular sizes for medium storage devices you'll find a two zone where the fans will be aligned to remove the airflow choke from the HDD's but in the cases without HDD's you'll find that they contain minimal fans and the cooling requirement goes down dramatically (of course depending on use case here). Its rare to see a fan attached to a heat sink unless its a high core count. Where its hard to compare to servers is the cooling of MOSFETS is easier than cooling more delicate parts like a CPU.


The Beheringer doesn't have a massive cooling requirement unless you are really thumping the tunes, its a bit more open than a server case will be and I think that's why they included the shroud over the MOSFETS. The newer NX series does include a heatsink.
 
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