Hi,
I don't understand a part of the high voltage power supply of the ADA MP-1 schematic (see attached)
It seems that the ground reference is controlled by U2, but why and how ? It looks like a log amp topology, which if I understand correctly, acts like an envelope follower. But I don't understand what it does exactly.
Why not just connect the negative rectifier bridge side to ground directly ?
The ground reference will be separated by few kohms (R10) and -15V rail of the rest of the circuit ground reference. Or am I missing something ?
Note that the two first triodes are referenced to -15V, not ground. Does it justifies the U2 circuit ?
Can you explain the purpose of this circuitry, and it's advantages compared to a classic bridge rectifier configuration ?
Thanks