> . What is the purpose
> of the 3 x 1N4001 in place of the link to the bases.

Reduce output x 3 x Vd ~=3D 1.8V.
Vout can be V_LM317 - 3 x Vd - Vbe_2N3055 ~~~~=3D 0V min if Vee is grounded=
..

If Vee is < ground then cct can go to ground without the diodes  (maybe).


ie As LM317 goes to minimum of 1.25V this allows Vout to go to ~=3D true Ze=
ro.

>  And the 1N5401 feedback from
> Vout to supply ?

That's a reverse discharge diode for when Vin is removed and you may
have larghe caps on the output (not shown).
Without this diode, if Vin is interrupted the cct may be reverse
biased by whatever Vout was - which may or may not cause damage
otherwise.

__

Under low to no load with 34VAC then Vincap can go to 34 x sqrt(2)~=3D 48V.
R plus zener will clamp this.
Deep-ending on transformer etc power loss in series R may become significan=
t.
At 320 mA losses are ~=3D 100 mW per ohm of dropper or 0.32 W per volt of d=
ropper.


             R
--=20
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