First watt F2j with SJDP120R085

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no need for that

upper mosfet is "just" decent CCS
 

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Aside from the lowish Pd, the Wolfspeed C2M0280120D looks like a nice part.

Approximately a 4:1 safety margin in the F2.

I seem to recall trying these in an AMP CAMP a year or so ago and the distortion was roughly cut in half. I could be mis-remembering :geezer:

Thanks Michael. Apologize for showing off my ignorance and poor reading skills.

No need to apologize, this is the happy fun crew 🙂 There's plenty of confusion about power JFETs in their various forms.

But if you misbehave we throw you out the little round window on the side of the boat. :Pirate:
 
Zenmode it is hard to source those SJEP jfets. Do you know any other drop in replacements ?

If you do have a nicely matched quad of SJDP120R085, I do have this quad of SJEP120R125 where we could swap. Measurement was provided by Dr. Mazolla (Semisouthfan).

I'm not interested in swapping with unmatched R085 though. PM me if interested.
 

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Thanks Zen mod. More questions as I am collecting parts. What should be the Value of L1?
What should be the power supply rated minimum?
How can I calculate heat sink requirement for passively cooled design?

Papa is routinely using 300VA xformer for stereo amp
just take al ook at any one-polar FW PSU

L1 is drawn as separate but somewhere in text is explained as internal inductivity of locally connected series wirewound resistor


:rofl:
 
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