Version 4
SHEET 1 2680 712
WIRE 912 -128 560 -128
WIRE 1056 -128 1008 -128
WIRE 1200 -128 1056 -128
WIRE 1200 -64 1200 -128
WIRE 560 -32 560 -128
WIRE 576 -32 560 -32
WIRE 688 -32 656 -32
WIRE 720 -32 688 -32
WIRE 880 -32 800 -32
WIRE 960 -32 960 -64
WIRE 960 -32 880 -32
WIRE 352 -16 256 -16
WIRE 256 16 256 -16
WIRE 1056 16 1056 -128
WIRE 688 32 688 -32
WIRE 880 32 880 -32
WIRE 960 32 960 -32
WIRE 1200 32 1200 16
WIRE 256 128 256 96
WIRE 352 128 256 128
WIRE 688 128 688 96
WIRE 688 128 560 128
WIRE 880 128 880 96
WIRE 880 128 688 128
WIRE 960 128 960 96
WIRE 960 128 880 128
WIRE 1056 128 1056 96
WIRE 1056 128 960 128
WIRE 560 144 560 128
WIRE 256 160 256 128
WIRE 688 160 688 128
WIRE 880 160 880 128
WIRE 960 160 960 128
WIRE 1056 160 1056 128
WIRE 352 176 352 128
WIRE 1200 224 1200 208
WIRE 256 272 256 240
WIRE 352 272 256 272
WIRE 576 288 560 288
WIRE 688 288 688 224
WIRE 688 288 656 288
WIRE 720 288 688 288
WIRE 880 288 880 224
WIRE 880 288 800 288
WIRE 960 288 960 224
WIRE 960 288 880 288
WIRE 960 320 960 288
WIRE 560 384 560 288
WIRE 912 384 560 384
WIRE 1056 384 1056 240
WIRE 1056 384 1008 384
WIRE 1200 384 1200 304
WIRE 1200 384 1056 384
FLAG 352 176 0
FLAG 352 -16 +24V
FLAG 352 272 -24V
FLAG 560 -128 +24V
FLAG 560 384 -24V
FLAG 560 144 0
FLAG 1056 -128 +Vout
FLAG 1056 384 -Vout
FLAG 1200 32 0
FLAG 1200 208 0
FLAG 2400 -112 +24V
SYMBOL voltage 256 0 R0
SYMATTR InstName V1
SYMATTR Value 24
SYMBOL voltage 256 144 R0
SYMATTR InstName V2
SYMATTR Value 24
SYMBOL res 672 -48 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value {RCUR}
SYMBOL cap 672 32 R0
SYMATTR InstName C1
SYMATTR Value 100µ
SYMBOL cap 672 160 R0
SYMATTR InstName C2
SYMATTR Value 100µ
SYMBOL zener 896 96 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D1
SYMATTR Value TFZ18B
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL cap 944 32 R0
SYMATTR InstName C3
SYMATTR Value 10µ
SYMBOL cap 944 160 R0
SYMATTR InstName C4
SYMATTR Value 10µ
SYMBOL res 1040 0 R0
SYMATTR InstName R5
SYMATTR Value 10k
SYMBOL res 1040 144 R0
SYMATTR InstName R6
SYMATTR Value 10k
SYMBOL npn 912 -64 R270
SYMATTR InstName Q1
SYMATTR Value BC847A
SYMBOL pnp 912 320 M90
SYMATTR InstName Q2
SYMATTR Value BC857B
SYMBOL res 1184 -80 R0
SYMATTR InstName R7
SYMATTR Value 18
SYMBOL res 1184 208 R0
SYMATTR InstName R8
SYMATTR Value 18
SYMBOL zener 896 224 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D2
SYMATTR Value TFZ18B
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL PowerProducts\\LT317A 2544 -112 R0
SYMATTR InstName U1
SYMBOL res 816 -48 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value {RCUR}
SYMBOL res 816 272 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value {RCUR}
SYMBOL res 672 272 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value {RCUR}
TEXT 1512 -272 Left 2 ;Vout = Vin - Vzener\nR1 = R3 = Vout / (Izener + Ibase) \nP = Vout^2 / R1   (P is power dissipation of R1 and R3 in mW)\n \nV1 = 56V\nV2 = 56 - Vzener = 32V\nR1 = R3 = 32 / 20m = 1.6k (use 1.5k)\nP = 32² / 1.5k = 682mW = 0.68W (use 1W)
TEXT 726 -266 Left 2 !.tran 0 0.1 0 0.0001
TEXT 1512 96 Left 2 ;https://www.youtube.com/watch?v=ur3nUWHKhtA
TEXT 1512 120 Left 2 ;https://sound-au.com/project102.htm
TEXT 1488 240 Left 2 !.ic V(+Vout)=0 V(-Vout)=0
TEXT 1496 304 Left 2 !.param RCUR=200
