View Full Version : Heatsink requirements for amp7 and amp15
How big heat sinks are needed for amp15 and amp7?
Are you interested in an estimate by mr. some uneducated guy? (That would be me.)
If we assume 80% efficiency of MAX_POWER, then ~ 20% of MAX_POWER is heat.
Amp7 is 2x500 = 1000W max, so we could conceivably see 200W of waste heat at full tilt. Then you could conceivably plug in the temperature spec, and find out a ballpark degrees per watt ...
The worst case heatsink for Amp7, assuming that maximum temp is 130 degrees, and 30 deg ambient, would be 0.5 degrees C per watt. When playing full-tilt sinewaves at 1000W into an inefficient load.
For Amp15, 2.5 degrees C per watt.
Hope this helps rather than hurts. I don't know enough to be talking about this really ...
Want an even less reliable estimate?
Amp15 I am using a 3mm thick aluminium plate the same size as the amp15's pcb. It doesnt even get warm, so it must be overkill.
Thanks guys, krillis maths appears to be solid :-)
I intend to mount the apms on a heatsink that is a bit larger than the amp, in order to be able to mount the heatsink without any problems on the front plate of a 3U 19" case.
Aavid heatsinks for amp7: http://www.aavidthermalloy.com/cgi-bin/euro2_exsrch.pl?Pnum=&PgNum=1&NumPerPage=v3&LengthUnits=mm&ExLength=130.00&WidthMin=170.00&HeightMin=0.00&WidthMax=210.00&HeightMax=999.00&ThermalResist=1&CType=Natural&AirFlow=&AirUnits=ms&Shape1=ON&Shape2=&Shape3=&Shape4=&Shape8=&Shape5=&Shape6=&Shape7=&SortBy=V2&PartClass=A&ClassA=0&ClassB=0&ClassC=0
Heatsinks for amp15: http://www.aavidthermalloy.com/cgi-bin/euro2_exsrch.pl?PgNum=1&PartClass=A&ClassA=0&ClassB=0&ClassC=0&LengthUnits=mm&WidthMin=170&WidthMax=210&HeightMin=&HeightMax=20&ThermalResist=2%2C5&ExLength=130&CType=Natural&AirFlow=&AirUnits=ms&Shape1=ON&SearchButton1=Search&SortBy=V2&NumPerPage=v3. I guess this is overkill :-)
AMP7 is fine with a sheet the size of the PCB in 2 or 3mm aluminium.... It's just always stone cold...
I do normally give it some more to be sure...
------X-max. can be several meters on any driver, too bad it can be done only once...------
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