AKG N61A Power Supply - new design

[dustbro]

Hey guys!
My C61 PSU has seen better days. PCB is cracked... Some pads are missing... So I'm looking to build a new supply for the mic.
Can I get another set of eyes on this schematic to  error check?
The new design is without the -7 / -12 pads.

 

[dustbro]

original schematic:

 

[Walrus]

The dissipation in the 5k trimmer will make it very hot!

 

[dustbro]

How so?

 

[PRR]

> How so?

Do The Math!!

R1 passes 1.2V/240r= 0.005 Amps into R2.

Output voltage is supposed to be 120V, so around 118V across R2.

118V * 0.005A is 0.59 Watts.

Most trimmers are rated 0.25W, maybe 0.5W.

Smoke. Or maybe just slow disintegration.

AND.... you do NOT need full-range adjustment from 1.25V to.... wait a second, 1.25V times 5240/240 is 27V, not 120V! The R2 leg must be near 23K, not 5K.

This suggests 20K fixed plus 0-5K trim, for 105V to 130V trimmability. Max dissipation in the trim is 0.005A^2 * 5000 or 0.125V, acceptable in a 1/4W trimmer.