F5 Turbo Builders Thread

on heatsinks... I think that ones from the store chassis have a bit to thin base. With not enough thickness of the base you can have a big temp. gradient(hot near transistor and cool further). Thats what I have with my F5T. I ordered 3/8"x6"12" aluminum bars and will use them to increase base thickness of my sinks. I will let you know if it helps.
 
I posted a link in the Solid State heading but as the F5T makes use of a MOSFET output stage I thought I'd ask the question here too. Can anyone please give me an answer on what the difference is between placing the series resistor between the mosfet Drain and supply vs placing the resistor between Source and the load.

On my simulation the series R between Supply rail and mosfet Drain gives the lowest harmonic distortion figure, why?

Here is the original post with schematics of the final stage

http://www.diyaudio.com/forums/solid-state/231535-rd-rs-mosfet-output.html
 
Another thing, I just have no ideas how sinks for the store (or hifi2000.it) have such good dissipation numbers. From my humble knowledge ones from heatsinkUSA should be much more efficient, but they not...

the C/W ratings depends on temp. if they measure C/W ratings at 80C above ambient, the numbers will look much greater then if they measure at 25C above ambient. there you have the difference.
 
They are black anodized, the HeatsinkUSA are raw. That will make a difference.

Of course, you can anodize the HeatsinkUSA 'sinks and make up said difference.

At given temperatures radiational contribution in heat "transport" will be much smaller compare to convectional contribution. So I would speculate that AudioSan right -- it is more how you measure it.