Motional feedback amplifier based on Philips 40 wats amplifier 1970s

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Hi all
I fond Motional feedback amplifier when i browsing it make some changes in original Philips 40 wats amplifier lat 1970s
 

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HI i prifard to use tweeter & woofer because this amplifier don't need passive filter with tweeter hi frequency response is very good can you give me some suggestion about this amlifier

I know that this is old thread...

but could you elaborate why/how this amplifier don't need passive filter with tweeter hi frequency? is it because you have two seperate amp for low and hi part? (bi-amping with active x-over or passive network in front of the amp?)
 
This basically a schematic of a simple (typical) Class AB amplifier design that uses current feedback instead of voltage feedback via the .47ohm resistor in series with the output load to ground and the 470ohm resistor going back to the input transistor.

It appears that the motional feedback section had not been implemented yet.

FWIW

jer :)
 
It's an amp providing a negative output impedance through positive feedback by bootstrapping the input node between the two 150 kOhm resistors.
The idea is very ancient, see Werner and Carell, JAES October 1958, for example, Thiele also details it in his BR papers.
 
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