SemiSouth boiler room

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Buzz,

The second article, long in coming (sorry), is about distortion reduction from load-line canceling, and measurement and modeling methods to assist DIY'rs to estimate performance of SemiSouth JFETs (and other transistors) in amps.

I plan for a third article to be on other forms of negative feedback, with a particular look at source degeneration. From my analysis, for example, the 0.6 Ohm of Rs in an F2J contributes to THD reduction. It is likely that anything in the range you quote will make a difference.
Hi Mike,

Any news on Parts II and III of your article? btw, thoroughly enjoyed Part I. :hypno2:
 
Absolutely! Turning all available gain into "degenerate" feedback is a powerful linearisation tool. But the "sweet spot," according to Nelson's article on the matter, can be discerned in favor of the SemiSouth power jfet even when all of the competing transistor choices are operated as source or emitter followers as well. That's because, in my opinion, of the shape of the curves in the output characteristics which the SemiSouth power jfets have unique to themselves.

But that is the subject of Part II, which is way overdue, but mostly written. Sorry all you patient souls!!

I owe, I owe, it's off to work I go...

Do these power jfets also have lower distortion when used as a source follower ?
 
So what about this as an idea. Here we can minimize the dissipation of the jfet using the cascode fet, the same fet that we might otherwise use to regulate the B+ .
 

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What's the Buzz - Part II

Attached is the second part in a three part series entitled "What's the Buzz?" The document and a supporting spreadsheet are included in the zip archive. I had to reduce the resolution of the pdf document to fit under the upload file size limit imposed by the forum. If you prefer slightly better resolution, email me and maybe I can arrange for the higher rez document to be available on a file uploader site.

Many of you have encouraged me throughout the more than one year it has taken me to research and write the second installment. Well! I"m glad to finally be able to push the post button and get this off my chest. It's like a good confession, it really puts the mind at ease.

Anyway, as before, this is the next step in my goal to understand why you guys like the SemiSouth JFET so much.

As before, I hope you find it both worthwhile and entertaining to read. The subject of Part III, negative feedback, is hardly a topic calculated to get the next one out in a timely manner, but your encouragement does really help.
 

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Awesome!

SemiSouthfan,

I/we really appreciate you taking the time to put this together. I'm looking forward to learning from it. Part I was excellent.

I keep hoping the products will get re-released at some point. I think the demand would be there.

Thanks again,

Steve
 
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