Square Law Class A Amps

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Padamiecki this page might hold some interest for, look at the third circuit.
Only Distortion Negative Feedback Circuit

I don't see anything here that is not classical feedback, only differently arranged.
Classical feedback says that distortion approaches zero if beta*Aol approaches infinity.
That is exactly the condition in this article, with Aol replaced by K*D. Same thing.

jan
 
Padamiecki this page might hold some interest for, look at the third circuit.
Only Distortion Negative Feedback Circuit

I knew this site,
what I wanted to show
is an interesting output circuit with grounded sources/emmiters.
This of course makes relatively high output impedance
but
this makes current output which sounds so good (only peak resonances of the woofers/tweeters have to be dumped);)
 
Ian Hegglun's Square Law Class A

I've been in contact with Ian Hegglun and he helped me simulate figure 4 from his Linear Audio, Volume 1 article. Ian has also been very helpful answering questions in regard to this circuit. Ian's skill as a design engineer is very impressive; he's put a lot of good engineering practice and thought into his Square Law designs.

Attached are screen shots and LTSpice simulation files. Ian tweaked the EKV transistor models to simulate square law behavior. I'm also using some of Bob Cordell's models.

This circuit will be my next amp project.
 

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AX tech editor
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But much bigger currents of 2A peak in T1+T2 are linear class A.
I don't see where the efficiency is supposed to come from?

Which currents are these? With output signal? The bias currents should be much, much lower, so although the circuit 'works' like a class A circuit, the bias current (and thus the eficiency) is of a class AB circuit.

jan
 
Which currents are these? With output signal? The bias currents should be much, much lower, so although the circuit 'works' like a class A circuit, the bias current (and thus the eficiency) is of a class AB circuit.

jan

The bias current for T1, T2 is 1.13 A when I simulated it, so it is class AB but very deep one. For T3, T4 is 26 mA only. The power dissipation wile idling is 76W and this is not so low.
How to to thermally stabilize this combination of lateral and vertical MOSFET output transistors?
dado
 
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