EF2 output stage with 2SJ76/K213 as driver

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Joined 2002
#1
Was looking at a Kenwood car amplifier from the 90s. The output stage consisted of a pair of 0.5 A MOSFETs and 20 MHz Sanken BJT output transistors.

Looking at the data sheet, the input capacitance is highish (120 pF) and the equivalent fT only about 15 MHz.

https://www.web-bcs.com/pdf/Hit/2S/2SJ76.pdf
I can see the attraction of not having beta droop loading the VAS and possibly some positive TC (not sure this is the case here) stabilizing the idle current, but in terms of bandwidth and nonlinear capacitance, I suspect many bipolar drivers will be superior. Your take?
 
#3
Well, it's a far cry from the usual "symmetrical" LTP (i.e. NPN and PNP pair), dual VAS, EF2 affair. Single LTP, folded cascode and symmetrical VAS, the lower half of which is driven from another current mirror. They clearly wanted low distortion.
 
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