# Amp rack Hush Box ideas and questions



## chrapladm (Jun 17, 2009)

I have been searching and searching for an amp rack that I can use to house my amps in a closed environment. I am wanting to have something that can house 4 amps roughly, have the door shut for quiet operation and yet keep the air circulating enough to keep the amps cool.

These are my ideas for looks:


















So after seeing all the different racks available and then seeing the price fo the ones I liked I am deciding I will just have to build my own. The quality wont be as nice as the manufactured ones but as long as it is functional and works thats all I care about.

I would like to be able to have an access door on the front that when using the HT system the door will remain closed. SO I will need help in figuring out how to implement the correct number of fans for air flow for the amps.

Main construction material being used will be MDF also.

Any ideas or help would be greatly appreciated.


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## ALMFamily (Oct 19, 2011)

Papi,

I am not sure if this will help or not, but when I was trying to figure out what size fan to do for my equipment closet, Ryan (Negativeentropy) gave me this:

_Or, use the calculator here as follows:

Take the volume of your equipment room in cubic meters, multiply by 1.2 to get the mass of the air in kg (change the units in the calculator to match).

Use 18 degrees F for the temperature change (86-68). Again, make sure the units are set to Deg F or Rankine (same thing).

Leave the "Quantity of heat needed" blank, but make sure the units are in "J" or joules.

The specific heat capacity of air is 1.0, change the units to KJ/Kg.C(K)

Click calculate.This will generate the quantity of heat needed in Joules. A Watt is a Joule per second, so divide the Joules number by the Watts your equipment consumes in the room to get the seconds required to heat the air in the room.

For example, a 4 cubic meter room has 4.8 kg of air in it. The calculator shows 48000 J to heat the room by 18 degrees F. At 400 watts that's only 2 minutes.

Now, this calculation makes a pile of assumptions we know to be false, but it should be good to a first approximation.

It also gives you what you need to calculate a reasonable minimum airflow for the room. The above example of 4 cubic meters equals 141 cubic feet. If it takes 2 minutes to heat the air, changing out the air in the same 2 minutes should provide adequate cooling. So that would mean only 70 cfm (minimum) of air exchange is needed.

Make sure the wattage number you use is realistic - preferably from actual measurements. 

_

I never really ran the numbers as Ryan did the calculations for me, but it may help you to get an idea.


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## chrapladm (Jun 17, 2009)

I will try and use it and see what I can get from it. Thanks.

I have a feeling I will probably try and wing it and add rack fans until I get a consistent average temperature.

I also have to try and figure out what I will need to use for walls as far as thickness. I am thinking of just using MDF and sealing the cabinet to some degree then using temperature aided fans to pull the heat out. 

I am curious which is the easiest way to have heat vented out? With amps that cool back to front and should I have exhaust fans on the front?

Or could I have fans on the top rack space pulling air up and then have exhaust fans facing the rear?


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## ALMFamily (Oct 19, 2011)

I would opt for the 2nd option as it allows you to help somewhat bury any fan noise. That said, I am not sure where it would be located. If you have the back close to a wall, you might not get optimum venting doing it this way.

Are you planning on making it an end table or something akin to that? If not, what about mounting the fans on top and pulling the air up and out?


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