Thee PCBs were more elaborate than the 35-01, The IPS and VAS were generally cascoded. There was an inter-stage buffer between the VAS and the output stage. The output stage remained quasi-complimentary triples with a diode to improve the symmetry. Stability was achieved without the use of the VAS Miller integrator capacitor. Instead Miller inclusive compensation, (plus an internal pole zero lag) was applied with several advantages:-
1 Higher slew rate
2 Much lower current modulation in the LTP stage.
3 The cascode VAS was much more linear and was loading the input stage less due to higher Hfe of the lower device.
4) The class A buffer between the VAS and the triple EF output stage made VAS loading extremely minimal and maximised the open loop gain.