nania said:
On my A75 I placed my mosfets also at the very top and it works fine. For my design it was the only way to go if i wanted to have PS at the bottom http://www.passdiy.com/gallery/a75-p7.htm
When I touch heat sink after everything settles down the temperature is even.
R-Theta has a program for thermal behaviour of a sink.
The base is 13" square the tower is 20' High. it is comprised of 8 Heatsinks 8x10 with .750 fins. The structure is assembled around 4, 1 inch square Aluminum bars which would act as Rails to mount the TO-247 IRFP244 FETs There are 2 or 4 60 MM 12VDC fans running at 6VDC as intakes on the bottom and 1 5.25 12 VDC fan running at 8 VDC on top as an exhaust. All fans run below audible levels.
Actually it is not, a scanning device by definition scans an image with a reflective light source moving sequentially across a glass plate which has an optic focused on it to return the refracted light to a CCD. The elements of the CCD are not activated until it is passed the scanned light.
In a Digital camera when the "Shutter" opens, (CCD is activated) the incoming light through the optics activates all elements at once. The on board microprocessor reads each pixel sequentially and stores the Data. Although this can be referred to as scanning, it is really a misnomer.
Anthony
When mounting heat sinks, I have always had the fins on the extrusion running vertically and cutting it to length. I have noticed that a common practise employed by DIR'ers on this board is to mount the extrusion with the fins Vertical. This would limit the depth of the chasis to the Extrusion width. The chassis would end up being taller as opposed to longer. Is this due to the belief that convection is improved by the different orientation of the Heatsink Fins?
Anyone care to banter this issue with me?
Anthony
Anyone care to banter this issue with me?
Anthony
I actually made a test with my SOZ at two operating temperatures:
At 102ºC (ouch!) the temp didn't change with the vertical/horizontal configuration.
I tried also with a horizontal configuration with the fins up (the heatsink is horizontal and the fins vertical). this way the temp was 98-99º.
At 50º horizontal fins corresponded a vertical configuration of 48º, so I guess the configuration isn't that important, so I went for the looks
At 102ºC (ouch!) the temp didn't change with the vertical/horizontal configuration.
I tried also with a horizontal configuration with the fins up (the heatsink is horizontal and the fins vertical). this way the temp was 98-99º.
At 50º horizontal fins corresponded a vertical configuration of 48º, so I guess the configuration isn't that important, so I went for the looks
Re: Heatsinks
Here is my completed Chassis for my A75's. I have not sandblasted the heat sinks yet or added the power switch an I/O connections. I will send interior shots in a few weeks when I get back to the project. I have completed the mounting rails for the 48 Transistors, I did not want them mounted to the outside of the heatsink. I have four 60 mm fans on the bottom, one for each 12 Transistors, independantly controlled by a pair of Thermistors in parallel. The exhuast fan will run continuosly, all fans will be "Tuned" to thier lowest operating threshold to minimize noise. The columns are purely architectural and are designed to compliment the angluar lines and tie into to the feet which I machined to match my Audio stand.
I believe that great architectyre can make great art, I hope you can appreciate my A75 for the Art of it's design. That is what drew me to Mr. Pass and his designs in the first place. I beleive Mr. Pass also believes in the appeal of Art in his product.
Here is my completed Chassis for my A75's. I have not sandblasted the heat sinks yet or added the power switch an I/O connections. I will send interior shots in a few weeks when I get back to the project. I have completed the mounting rails for the 48 Transistors, I did not want them mounted to the outside of the heatsink. I have four 60 mm fans on the bottom, one for each 12 Transistors, independantly controlled by a pair of Thermistors in parallel. The exhuast fan will run continuosly, all fans will be "Tuned" to thier lowest operating threshold to minimize noise. The columns are purely architectural and are designed to compliment the angluar lines and tie into to the feet which I machined to match my Audio stand.
I believe that great architectyre can make great art, I hope you can appreciate my A75 for the Art of it's design. That is what drew me to Mr. Pass and his designs in the first place. I beleive Mr. Pass also believes in the appeal of Art in his product.
An externally hosted image should be here but it was not working when we last tested it.
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