The DPA 880 schematic

The DPA 880 low detail schematic (click on the image to see the high detailed version (48 Kb)

Do not try to print this picture in Netscape because it's too big.

Nothing much to discuss here :

Again, this one is similar to the above ones, only it uses serial connection in the power stage to allow a higher voltage.
The bias current is 110 mA.
The output coil is 14 turns of 1.8mm wire on an 11mm diameter.
The trafo should be about 2*57 Volts and 20 to 25 amps !!!