F6 Amplifier

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Joined 2006
Paid Member
Quote:
Originally Posted by lhquam
Heat dissipation is not an issue for such a low resistance. The idle power will be Ibias^2*R. For Ibias=1.5A, and R<0R44, the power will be less than 1 watt.

By KBK

Which means you can move to 3 watt surface mount foil.

http://www.digikey.ca/product-detail...8CT-ND/1936102


So is it okay to use .1R SMD Foils? For some reason I ordered 1W ones. I soldered leads to them, but now I am worried they are too little.

I suppose I should install and measure heat output.
 
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The one and only
Joined 2001
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The F6 with IR parts works fine - you need to degenerate the parts with
0.47 ohms or so (maybe a little more) for thermal stability, and you will
find that there is higher harmonic distortion. Typically an IRFP240 will come
in with about twice the THD figure, but as the overall amplifier also has a
distortion contribution from the transformer, you will not see a doubling of
distortion in the overall amplifier.

The primary value of the SS Jfets are less thd and thermal drift, but you can
get along fine with other parts.

:cool: