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Old 10th July 2003, 05:17 PM   #1
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Default Amplifier Cooling

For all you guys building nice, hot, class A amps, note that if you want the innards to run cooler than the heatsinks, you need to make ventilating holes of some sort in both the top and the bottom.

If you don't, it's just the same as if you never made the holes in the top! (Ask me how I know this!)

And I should know better. I used to be in the furnace business, and it's pretty fundamental that if air is to flow out, it must flow in (and vice versa).

The net area open to convection is the smaller of the open area in the top or the bottom.

If you don't ventilate, the air contained in the box will come up in temperature over time until it's just about equal to that of the heatsinks.
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Old 10th July 2003, 05:24 PM   #2
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since your a furnace guy vince lets talk about static pressure inside a cabinet and inlet and outlet sizing sizing??????

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Old 10th July 2003, 05:25 PM   #3
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oh, how do you know this?
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Old 10th July 2003, 05:47 PM   #4
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Vince,

Like this http://www.diyaudio.com/forums/showt...2763#post92763 do you mean?

Chris
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Old 10th July 2003, 05:59 PM   #5
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Sometimes I'm seriously thinking about the air flow holes.
If the amp is getting very hot and fresh air is supplied inside it, it might ignite a fire. Therefore, I prefer a totally closed box having laaarge size of heatsinks on its sides.

...

JH
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Old 10th July 2003, 07:10 PM   #6
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The panels I plan to use for my ZenV4's have a double row of 3 mm holes near the heatsink. The top panel are crossdriled all over.

Didn't do this my self... the panels came of an old 5u high 10mbit network switch
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Old 10th July 2003, 09:47 PM   #7
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This is also an issue with the X Aleph.

There is siginificantly more heat generated losses from the internals such as chokes/resisters, rectifiers and even the transformers who are being asked to deliver twice the current.

The losses in heat (50-100 watts)from these components have to go somewhere, and obviously the air temperature in the box will rise appreciably as a result without ventilation.

Heatsinking these items to the outside world would help, but this must them be then accounted for in the heatsink surface area.

The box must still be ventilated or the air temperature will approach that of the heat sinks.

I am sure many who are currently building their monster X Aleph will be surprised to find their box is too hot without ventilation, even with the lid off(ie holes in the bottom)

I recently did the upgraded from the Aleph 2 to the X Aleph 100 and I propose to deal with this in revision 1 of the chassis- layout.

This will mean re arranging the position of the transformers to be each placed on the floor of the box (the coolest place), each surrounded be vent holes (at moment stacked on top each other for space reasons).

I also plan a row of vent holes along the length each side of the floor of the box (1 cm))

The rectifiers, which gernerate a lot of heat will be moved and bolted the a large channel section each side of the box for heatsinking.

The capacitor smoothing filters will be supported well above the transformers on a channel section, with the driver board mounted horizontally at the rear...it will look not unlike a Pass X Series.

I am not sure about the lid yet, there will be holes . but maybe a fan for the summer as well!!

I hope this helps illustrate some the facts about this hot topic.

Here is an image of some of the hot parts.

macka
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Old 11th July 2003, 05:37 AM   #8
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JH said:
"Sometimes I'm seriously thinking about the air flow holes.
If the amp is getting very hot and fresh air is supplied inside it, it might ignite a fire. Therefore, I prefer a totally closed box having laaarge size of heatsinks on its sides."

Flames won't make it past a metal mesh so use some metal window screen to cover your ventilation holes if you are worried about fire. Just an idea.
Greg

BTW What is the source of fuel for this fresh air induced combustion you anticipate? Does your Aleph run on petrol?
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Old 11th July 2003, 11:45 AM   #9
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jh6you,

In certain industrial environmental conditions intrinsically safe operating enclosures (explosion and dust proof) are necessary.

This is for areas like grain silos, coal mines & treatment plants or other areas were the possibility of instantanious conbustion from air born dust particles is a concern.

Your average living room should be okay....unless of course you are a mad scientist (by the name of Pass..muhahahah..just joking) or you are prone to erratic Fart Attacks.

macka

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Old 11th July 2003, 12:15 PM   #10
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I just wanted to put fire in this thread.

Yes, my amp have number of openings both at deck and at bottom.
I however havn't counted exact number of openings. I agree the
same area of air inlet and outlet openings is the right answer.

JH
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