For servo duty, there are some newer TI offerings which look worthy. That is assuming that lowish noise and bias currents are desirable (they would be to me if I were seeking out a servo amp). OPAX141, OPAX376 and OPAX209. The latter is bipolar but has lower noise than any JFET I've seen coupled with commendably low input bias current for a bipolar.

https://www.diyaudio.com/forums/power...lator-128.html

voltage multiplyer: Cockcroft-walton

https://members.tm.net/lapointe/cockcroft_walton.htm

Allison simulation threadhttps://www.diyaudio.com/forums/solid...ut-stages.html

JLH schematics https://www.tcaas.btinternet.co.uk/jlhupdate.htm

last image of pos board #1110 https://www.diyaudio.com/forums/power...lator-111.html
version 5k post #1087https://www.diyaudio.com/forums/power...lator-109.html

Keantoken C multiplyer
Here is the output impedance using the 2SC4793/A1837 pair. This rivals some of the best electrolytics I have measured. It would be hard to improve on this using anything but film caps.

Post #1225

post1259, latest version
Q2 & J6 should be fed from the supply rails, not from the measurement rails.

What voltage (Vdg) is across the BF862 when they are set to 2 to 4mA?
I think you should be using a low Vpinch off for some of these locations, particularly J5 and maybe J6.

https://www.national.com/rap/Applicat...570,28,00.html

OS-Con Capacitors
https://archive.chipcenter.com/eexpert/akruger/akruger007.html

Vishay MKP capacitors at Digikeyhttps://search.digikey.com/scripts/Dk...+63V&x=26&y=21

Reflektor Notes: https://www.diyaudio.com/forums/power...ml#post2724088 post 4287

B1 with Shunt https://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer-2.html#post1854512

https://www.diyaudio.com/forums/power...ml#post2223856

schematics #1983 https://www.diyaudio.com/forums/power...ml#post2103465

Transformer R-Core EBAyhttps://www.ebay.com/itm/110V-50W-R-c...item4ab0dbf733

V1.2R schematics

https://www.diyaudio.com/forums/power...lator-320.html

board design starts 2384

Sense wire: Use RG58 on all your shunts for...

https://www.diyaudio.com/forums/digit...ification.html

more on setting up sound card for measurementshttps://www.diyaudio.com/forums/solid...rements-9.html

The ones I posted as symmetric 1.2 in page# 190 can do for +/-24V. Those are the ones that Bill initially tested for supplying his OP AMPS. There is a Q2 2N5459 JFET which is 25V VDS max that will set a 30V absolute max Vin given that it sits on 1.85V and there is a Vgs and R1 drop above it. Respect that Vin max. That Q2 must have 7mA or more IDSS for the cascode to work efficiently for a 7-9mA 2SK170BL Q9 under it with the given R4 (220R). If you want to feel free from Vin restrictions or choosing JFETS, you can do the BJT cascode left side. See post #2432 for negative example.
Making an additional positive one like those for 5V, only needs R13 1k trimmer to be 5k trimmer so it can go that low.
R1 is changing current setting, by 0.6V/R1=CCS current. Steadily predictable because that 0.6V is Q7's Vbe. Does not vary significantly per part or batch as with Leds Vf.
As for Vref and output caps subjective preferences, as Andrew said.
Good luck!
...

Hi,
a dual secondary 40+40Vac transformer will give ~58 to 59Vdc.
With good smoothing and a well built amp you can easily achieve 150W into 8r0.

If you want to have the ability to drive a 4ohm load then you will need to double the smoothing capacitance and double the VA rating of the transformer.

For 150W into 8r0, a 300VA with +-20mF will do.

My 230:40+40Vac gives +-58.5Vdc when fed with 240Vac and the amp bias is 220mA. It gives 170W into 8r0 from a 3pair output stage.

The power supply application note is available at https://www.national.com/an/AN/AN-1849.pdf

build the right half of the PSU in the app-note (Fig.1) and instead of all the soft-start/relay fun, put a thermistor, CL60, in series with the primary leads of the transformer.

transformer https://in.farnell.com/united-chemi-con/esmh800vnn103ma50t/cap-alum-elect-10000uf-80v-snap/dp/1363662

Andrew T notes on sizing...

https://malzev.tripod.com/book/butter.htm

Inductance Calculatorhttps://www.consultrsr.com/resources/eis/induct5.htm

LRC calculator https://www.calctool.org/CALC/eng/ele...cs/RLC_circuit