Beast with 1000 JFETs redux?

Naaah, assume the worst case distribution, the one guaranteed to give the smallest number of matches. MC with that and be pleasantly surprised.

Then buy a smaller pool, save time, spend less money, and get your 1000 matched pairs anyway. If you're unhappy with the number of matched pairs this yielded, you can buy some more units and do some more measurements.
 
The reason behind matching in this case is equal current sharing.

So if the bias current differs by 20%, there will be 20% more heat, and hence 20% higher dT.
If the JFET has -ve tempco at bias, it is self regulating, then not critical.
If it has +ve tempco, it tends to run away thernally (gets hotter and hotter).
So you are then trying to get 2000x within 0.1V Vp.

For the circlotron, from purely distortion point of view, you want 1000 pair, each pair well matched (to probably much better than 0.1V).
But you still need to solve the thermal issue somehow.


Patrick
 
Just to be clear, this is NOT on our list of projects in any foreseeable future.
My interest stops at Spice simulations.
So this will remain Nelson's exclusive.

We are working on something similar.
More down to earth (single devices), but no less exciting. 😉


Cheers,
Patrick
 
Just to complete the collection, why not just use ONE pair of matched Semisouths ?
Super simple to build, can even do P2P.
And since Semisouth is known to be about zero tempco, you can take full risk and use no source resistor.

Great performance as well. 😉


Patrick


PS Unzip the LIB file and place in same directory as .asc.
 

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The beast is inside the TO247 package when you inspect the bare die with a scanning electron microscope.

🙂


Cheers,
Patrick
 

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Extremely low distortion without negative feedback.

Okey, thats interesting, if what you are telling me is true.

Because low distortion does not seem to be the issue, that makes true musicality, of what i know to this date.

But i am going to build the H2 generator, and the Korg preamp, in the fall. And doing some more cool hifi testing.

But i am truely skeptic. Better then Aleph J. Naaah. Seems extremely unlikely, to be really honest 😇

And if it possibly sounded better: The marigin from Aleph J to Full Nirvana is slim to none. 💕😎

But unbeliveable things sometimes happens.