puzzled

[U102324]

The differential VAS has 180uA current per leg , a value quite low
since it drives directly the output mosfets capacitances ,
this should be increased ten folds at least.

This make me wonder if the original schematic used the ubiquitous 2N5401/
2N5551 pair instead....

The BD139/140 are well within power spec but are out of spec for Vce...

The original uses BD139/140 up to 40V and MJE340/50 to 70V

 

[wahab]

Someone needs to invent a simulator with a little bottle of blue smoke, so that excursions outside safe operating regions are more like real life!

I guess that it would take few time for most simulators users s rooms to be fully smogged,
if not the guys being asphyxied....

 

[wahab]

The original uses BD139/140 up to 40V and MJE340/50 to 70V

The second pair is awful , this had been unrelentlessely said in this forum ,
yet , the (bad) habits keep on going...