UK Toecutter,
can you post a fullsize image ...one side is enough, i'd like to see the pad size od some components, i'm so sure they are big enough for DIY.
Cooling?
Does anybody has an idea about cooling this beast? It appears to require about a .14C/W per channel. I do not know where to find a convection cooled heatsink that can handle that much heat with the MOSFETS concentrated on a 12" board. Forced air (fans) can easily provide a factor of 3x improvement over convection.
BTW: What are the dimensions of the F5-Turbo-v2/3 board?
Does anybody has an idea about cooling this beast? It appears to require about a .14C/W per channel. I do not know where to find a convection cooled heatsink that can handle that much heat with the MOSFETS concentrated on a 12" board. Forced air (fans) can easily provide a factor of 3x improvement over convection.
BTW: What are the dimensions of the F5-Turbo-v2/3 board?
There is no doubt in my mind that this is going to be the biggest consistent problem with this project. The heat rejection requirements are immense!
Still, where the is a will, there's a way, and I'm looking forward to seeing everybody's solutions.
Hi 6L6 you have seen myne already
Ihquam
Gogle up
gorini srl
any size you need up to 400 mm 16in wide and any lenght cut to mesure
If you need bigher ones they can weld 2 or 3 width togheter
From personal experience Quality is good
Price put to shame any other but shipping is the killer
>> GoriniSRL Main Page << Dissipatori di Calore in Alluminio
Ihquam
Gogle up
gorini srl
any size you need up to 400 mm 16in wide and any lenght cut to mesure
If you need bigher ones they can weld 2 or 3 width togheter
From personal experience Quality is good
Price put to shame any other but shipping is the killer
>> GoriniSRL Main Page << Dissipatori di Calore in Alluminio
2 x 0.28C/W is easy.
But Hey, if you like 18" deep amps, try Seifert KL147.
(me doubt you'll enjoy the fan noise at the 3x mark)
Hi 6L6 you have seen myne already
Ihquam
Gogle up
gorini srl
any size you need up to 400 mm 16in wide and any lenght cut to mesure
If you need bigher ones they can weld 2 or 3 width togheter
From personal experience Quality is good
Price put to shame any other but shipping is the killer
>> GoriniSRL Main Page << Dissipatori di Calore in Alluminio
I ran a NatSink convection simulation for the 400mm(W) x 83mm(H) x 200mm(L) heatsink with 8 MOSFETS dissipating 22 watts each. (400x83 appears to be the lowest C/W heatsink they make). The simulation shows a temperature rise of about 40C. Not good enough.
There are good low noise fans. I use a Noctua NF-S12-1200 in my F5 and the fan isn't noticeable.
I do the same with a "babysitter" for another class A amp i have , summer in Lisbon is Hot and i want to keep hearing music.
And ...the fans will be even quieter if run at lower than rated voltage, all we need is air movement really not a hurricane....
I get 20ºC lower heatsink temp with two of these fans on the "babysitter", one each side.
In winter i don't need this helper.
Here is a heatsink simulation based on using 1-1/2 HeatsinkUSA E007.
Unfortunately, HeatsinkUSA doesn't make anything wider than 256 mm, so I cut one E007 in half and weld it to a full E007 to make a 36 fin 384 wide. The resulting heatsink is 384 mm (W) x 130 mm (L) x 74 mm (H), with a baseplate thickness of 9.5 mm and has 36 fins. Too bad that such a heatsink isn't available off-the-shelf.
The simulation assumes 8 MOSFETs dissipating 22 watts each spaced according to the F5-Turbo-v2/3 layout. I also assume FORCED CONVECTION. The image shows the heat rise using .693 m/s air flow rate. Looks pretty good.
I imagine assembling two such heatsinks with the fins facing each other and using 3x 120mm low-noise fans in the same manner I used with the F5 shown HERE: http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-1021.html#post2453420
Unfortunately, HeatsinkUSA doesn't make anything wider than 256 mm, so I cut one E007 in half and weld it to a full E007 to make a 36 fin 384 wide. The resulting heatsink is 384 mm (W) x 130 mm (L) x 74 mm (H), with a baseplate thickness of 9.5 mm and has 36 fins. Too bad that such a heatsink isn't available off-the-shelf.
The simulation assumes 8 MOSFETs dissipating 22 watts each spaced according to the F5-Turbo-v2/3 layout. I also assume FORCED CONVECTION. The image shows the heat rise using .693 m/s air flow rate. Looks pretty good.
I imagine assembling two such heatsinks with the fins facing each other and using 3x 120mm low-noise fans in the same manner I used with the F5 shown HERE: http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-1021.html#post2453420
Attachments
Do you really want that much bias per fet .....?
What is the intended bias for the F5-Turbo? My number was based on the 800 VA power supply sizing.
81 cubic meter per hour (48CFM) is about 2m/s air velocity for a 4-2/3" gauge fan.
47.9 (0.2m/s) divided by 19.2 (2.01m/s) is ~2.5x
Still, very nice fan, the newer 100m3 model looks great, i want boat screws like that.
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