F5 Turbo Circuit Boards

[CeeVee]

Originally Posted by lhquam

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.

[UKToecutter]

Originally Posted by lhquam

BTW: What are the dimensions of the F5-Turbo-v2/3 board?

280mm x 50mm

[koja]

Thanks Andy.

Perfect. so I am in for two (2) amp boards (no PSU boards for me) please. cheers, >

[jacco vermeulen]

Originally Posted by lhquam

Noctua NF-S12-1200

Impressive fan.

[a.wayne]

Originally Posted by lhquam

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.

Do you really want that much bias per fet .....?

[a.wayne]

Originally Posted by jacco vermeulen

Impressive fan.

One would have thought curved blade (quite) instead of straight .....

[lhquam]

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: F5 power amplifier

[lhquam]

Originally Posted by a.wayne

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.

[labjr]

I made a post a few days back regarding heatsinking. Doesn't seem practical to have eight output devices on one heatsink.

[jacco vermeulen]

Originally Posted by lhquam

heatsink simulation

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.