[John L Stewart]

Here is just one of many possible hookups. It uses 4x6BX7GT to get 50 Watts of dissipation for the main losser. An IFR 840 n-Fet controls the grids, the combo looks like a very high mu triode.

That way not as much gain from the error amp is required. The error amp could be improved connected as a diff amp.

This example is loaded with 160 mA CC sources. The switches are marked (space), (X) & (Z), those being keyboard keys to control the OP range. The output load can be switched between 10 & 160 mA by key (C).

The pair of 0.2K resistors at the FWB rectifier help keep the input to the regulator low at a low range setting.

The voltages & currents indicated while the simulation was running.

Cheers to all, John