* SPICE netlist
Q1 Vpos InNeg N023 0 2N3904
Q2 Vpos N003 N006 0 NPN
Q3 N010 0 N009 0 2N3904
Q4 Vpos N006 N013 0 NPN
Q5 N021 N032 N034 0 NPN
Q6 N028 N031 N033 0 NPN
Q7 N021 N029 N032 0 NPN
Q9 N026 N030 N035 0 BF720/SIE
Q10 N027 N030 N036 0 BF720/SIE
Q11 Vpos N026 N030 0 BF720/SIE
Q12 Vpos N027 N031 0 NPN
Q13 N015 N010 N007 0 2N3906
Q14 N016 N011 N007 0 2N3906
Q15 N026 N023 N022 0 BF721/SIE
Q16 N026 N020 N018 0 2N3906
Q18 N027 N019 N017 0 2N3906
R1 N015 N022 1k1
D1 N004 N010 D
D2 N001 N004 D
R2 Vpos N001 1k
R3 N009 N008 1k
D3 N008 P001 D
D4 P001 MUTE D
R4 N016 N017 4k7
R5 N016 N018 4k7
R6 N019 0 10k
D5 N005 N011 D
D6 N002 N005 D
R7 Vpos N002 1k
Q19 N027 N025 N024 0 BF721/SIE
R8 N015 N024 1k1
R9 N035 Vneg 2k2
R10 N036 Vneg 2k2
R11 N033 Vneg 800
D7 N029 N033 D
R12 N034 Vneg 0.45
R13 N032 Vneg 150
R14 N006 N021 150
R15 N013 N021 0.45
D8 N003 N012 D
D9 N012 N014 D
D10 N014 N028 D
Q20 N029 N028 N021 0 PNP
R16 N021 N020 10k
C1 N021 N027 10pF
D11 N020 0 D
D12 0 N020 D
I1 N023 Vneg 0.5mA
I2 N025 Vneg 0.5mA
I3 N030 Vneg 10mA
I4 N031 Vneg 5mA
I5 N011 Vneg 1mA
Q17 Vpos InPos N025 0 2N3904
I6 Vpos N003 10mA
I7 Vpos N007 1mA
R19 OUT N021 0.0001
V1 Vpos 0 30
V2 0 Vneg 30
V3 InPos 0 SINE(0 0.2 10k)
R17 Out InNeg 1k
R18 0 InNeg 100
R20 MUTE Vneg 10k
C2 MUTE 0 1
R21 Out 0 4
.tran 1

* LTspice schematic (.asc)
Version 4
SHEET 1 2912 1600
WIRE 64 -800 -224 -800
WIRE 224 -800 64 -800
WIRE 432 -800 224 -800
WIRE 864 -800 432 -800
WIRE 1120 -800 864 -800
WIRE 1264 -800 1120 -800
WIRE 1456 -800 1264 -800
WIRE 432 -736 432 -800
WIRE 864 -736 864 -800
WIRE 64 -720 64 -800
WIRE 224 -672 224 -800
WIRE 1120 -624 1120 -800
WIRE 64 -608 64 -640
WIRE 432 -608 432 -656
WIRE -400 -592 -432 -592
WIRE 864 -576 864 -656
WIRE 1056 -576 864 -576
WIRE 64 -512 64 -544
WIRE 432 -512 432 -544
WIRE 1264 -512 1264 -800
WIRE 864 -496 864 -576
WIRE 1120 -464 1120 -528
WIRE 1200 -464 1120 -464
WIRE 224 -448 224 -592
WIRE 224 -448 176 -448
WIRE 288 -448 224 -448
WIRE -272 -400 -272 -592
WIRE -208 -400 -272 -400
WIRE -96 -400 -128 -400
WIRE 64 -400 64 -448
WIRE 64 -400 0 -400
WIRE 112 -400 64 -400
WIRE 432 -400 432 -448
WIRE 432 -400 352 -400
WIRE 864 -400 864 -432
WIRE 432 -384 432 -400
WIRE 1120 -352 1120 -464
WIRE 1264 -352 1264 -416
WIRE -1456 -304 -1456 -336
WIRE -48 -272 -48 -336
WIRE -48 -272 -432 -272
WIRE 864 -272 864 -336
WIRE 176 -256 176 -352
WIRE 176 -256 16 -256
WIRE 480 -256 176 -256
WIRE -1456 -192 -1456 -224
WIRE -1392 -192 -1456 -192
WIRE 288 -192 288 -352
WIRE 288 -192 240 -192
WIRE 336 -192 288 -192
WIRE 480 -192 480 -256
WIRE -976 -176 -976 -224
WIRE 16 -176 16 -256
WIRE -1456 -160 -1456 -192
WIRE -224 -160 -224 -800
WIRE -128 -160 -224 -160
WIRE 240 -160 240 -192
WIRE 336 -160 336 -192
WIRE -1216 -144 -1216 -176
WIRE -128 -128 -128 -160
WIRE -192 -80 -432 -80
WIRE -1456 -48 -1456 -80
WIRE 240 -48 240 -80
WIRE 336 -48 336 -80
WIRE -1216 -32 -1216 -64
WIRE -224 -16 -224 -160
WIRE 176 0 128 0
WIRE 528 0 400 0
WIRE 592 0 528 0
WIRE 640 0 592 0
WIRE 768 0 720 0
WIRE 1008 0 768 0
WIRE 1120 0 1120 -272
WIRE 1120 0 1008 0
WIRE 1264 0 1264 -272
WIRE 1264 0 1120 0
WIRE 1296 0 1264 0
WIRE 1424 0 1376 0
WIRE -288 32 -432 32
WIRE 128 32 128 0
WIRE 528 32 528 0
WIRE 592 32 592 0
WIRE 16 64 16 -96
WIRE -224 112 -224 80
WIRE -48 112 -224 112
WIRE -992 144 -992 112
WIRE -896 144 -992 144
WIRE 528 144 528 96
WIRE 560 144 528 144
WIRE 592 144 592 96
WIRE 592 144 560 144
WIRE -1344 160 -1376 160
WIRE -1296 160 -1344 160
WIRE -1184 160 -1216 160
WIRE -1168 160 -1184 160
WIRE 128 160 128 112
WIRE 560 160 560 144
WIRE -992 176 -992 144
WIRE 480 176 480 -112
WIRE -1184 192 -1184 160
WIRE -896 192 -896 144
WIRE -128 224 -128 -32
WIRE 416 224 -128 224
WIRE -1344 256 -1344 160
WIRE 1008 272 1008 0
WIRE -992 288 -992 256
WIRE -896 288 -896 256
WIRE 16 288 16 160
WIRE 336 288 336 48
WIRE 336 288 16 288
WIRE -1184 304 -1184 272
WIRE 480 304 480 272
WIRE 528 304 480 304
WIRE 768 304 768 0
WIRE 768 304 592 304
WIRE 864 320 864 -208
WIRE 944 320 864 320
WIRE 240 352 240 48
WIRE 480 352 480 304
WIRE 480 352 240 352
WIRE -1344 368 -1344 336
WIRE 160 416 160 368
WIRE 688 416 688 368
WIRE 1120 416 1120 0
WIRE 16 464 16 288
WIRE 96 464 16 464
WIRE 480 464 480 352
WIRE 624 464 480 464
WIRE 1008 464 1008 368
WIRE 1056 464 1008 464
WIRE 16 512 16 464
WIRE 480 512 480 464
WIRE 864 512 864 320
WIRE 1264 512 1264 0
WIRE 1008 528 1008 464
WIRE 160 560 160 512
WIRE 160 560 80 560
WIRE 416 560 160 560
WIRE 688 560 688 512
WIRE 800 560 688 560
WIRE 1120 560 1120 512
WIRE 1200 560 1120 560
WIRE 864 624 864 608
WIRE 1008 624 1008 592
WIRE 1008 624 864 624
WIRE 1120 640 1120 560
WIRE 1264 640 1264 608
WIRE 16 656 16 608
WIRE 480 656 480 608
WIRE 688 656 688 560
WIRE 864 656 864 624
WIRE -224 672 -224 112
WIRE -128 672 -128 224
WIRE 160 672 160 560
WIRE -224 800 -224 752
WIRE -128 800 -128 752
WIRE -128 800 -224 800
WIRE 16 800 16 736
WIRE 16 800 -128 800
WIRE 160 800 160 752
WIRE 160 800 16 800
WIRE 480 800 480 736
WIRE 480 800 160 800
WIRE 688 800 688 736
WIRE 688 800 480 800
WIRE 864 800 864 736
WIRE 864 800 688 800
WIRE 1120 800 1120 720
WIRE 1120 800 864 800
WIRE 1264 800 1264 720
WIRE 1264 800 1120 800
WIRE 1456 800 1264 800
FLAG 160 368 Vpos
FLAG 688 368 Vpos
FLAG 432 -304 Vneg
FLAG -432 -592 MUTE
IOPIN -352 -448 In
FLAG -432 -80 InPos
IOPIN -352 64 In
FLAG 1424 0 OUT
IOPIN 1504 144 Out
FLAG 1456 -800 Vpos
IOPIN 1536 -656 BiDir
FLAG 1456 800 Vneg
IOPIN 1536 944 BiDir
FLAG -432 32 InNeg
IOPIN -352 176 In
FLAG -432 -272 GndPin
IOPIN -352 -128 BiDir
FLAG 128 160 GndPin
IOPIN 208 304 BiDir
FLAG 560 160 GndPin
IOPIN 640 304 BiDir
FLAG -1392 -192 0
FLAG -1456 -336 Vpos
FLAG -1456 -48 Vneg
FLAG -1216 -32 0
FLAG -1216 -176 InPos
FLAG -1168 160 Out
FLAG -1344 368 0
FLAG -1376 160 InNeg
FLAG -896 288 0
FLAG -992 288 Vneg
FLAG -992 112 MUTE
FLAG -1184 304 0
FLAG -976 -224 GndPin
FLAG -976 -176 0
SYMBOL npn -288 -16 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL npn 1056 -624 R0
SYMATTR InstName Q2
SYMBOL npn 0 -336 M270
SYMATTR InstName Q3
SYMATTR Value 2N3904
SYMBOL npn 1200 -512 R0
SYMATTR InstName Q4
SYMBOL npn 1200 512 R0
SYMATTR InstName Q5
SYMBOL npn 800 512 R0
SYMATTR InstName Q6
SYMBOL npn 1056 416 R0
SYMATTR InstName Q7
SYMBOL npn 80 512 M0
SYMATTR InstName Q9
SYMATTR Value BF720/SIE
SYMBOL npn 416 512 R0
SYMATTR InstName Q10
SYMATTR Value BF720/SIE
SYMBOL npn 96 416 R0
SYMATTR InstName Q11
SYMATTR Value BF720/SIE
SYMBOL npn 624 416 R0
SYMATTR InstName Q12
SYMBOL pnp 112 -352 M180
SYMATTR InstName Q13
SYMATTR Value 2N3906
SYMBOL pnp 352 -352 R180
SYMATTR InstName Q14
SYMATTR Value 2N3906
SYMBOL pnp -48 160 M180
SYMATTR InstName Q15
SYMATTR Value BF721/SIE
SYMBOL pnp 400 48 R180
SYMATTR InstName Q16
SYMATTR Value 2N3906
SYMBOL pnp 176 48 M180
SYMATTR InstName Q18
SYMATTR Value 2N3906
SYMBOL res 0 -192 R0
SYMATTR InstName R1
SYMATTR Value 1k1
SYMBOL diode 48 -512 R0
SYMATTR InstName D1
SYMBOL diode 48 -608 R0
SYMATTR InstName D2
SYMBOL res 48 -736 R0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL res -112 -416 R90
SYMATTR InstName R3
SYMATTR Value 1k
SYMBOL diode -272 -608 R90
SYMATTR InstName D3
SYMBOL diode -336 -608 R90
SYMATTR InstName D4
SYMBOL res 224 -176 R0
SYMATTR InstName R4
SYMATTR Value 4k7
SYMBOL res 320 -176 R0
SYMATTR InstName R5
SYMATTR Value 4k7
SYMBOL res 112 16 R0
SYMATTR InstName R6
SYMATTR Value 10k
SYMBOL diode 416 -512 R0
SYMATTR InstName D5
SYMBOL diode 416 -608 R0
SYMATTR InstName D6
SYMBOL res 416 -752 R0
SYMATTR InstName R7
SYMATTR Value 1k
SYMBOL pnp 416 272 M180
SYMATTR InstName Q19
SYMATTR Value BF721/SIE
SYMBOL res 464 -208 R0
SYMATTR InstName R8
SYMATTR Value 1k1
SYMBOL res 0 640 R0
SYMATTR InstName R9
SYMATTR Value 2k2
SYMBOL res 464 640 R0
SYMATTR InstName R10
SYMATTR Value 2k2
SYMBOL res 848 640 R0
SYMATTR InstName R11
SYMATTR Value 800
SYMBOL diode 992 528 R0
SYMATTR InstName D7
SYMBOL res 1248 624 R0
SYMATTR InstName R12
SYMATTR Value 0.45
SYMBOL res 1104 624 R0
SYMATTR InstName R13
SYMATTR Value 150
SYMBOL res 1104 -368 R0
SYMATTR InstName R14
SYMATTR Value 150
SYMBOL res 1248 -368 R0
SYMATTR InstName R15
SYMATTR Value 0.45
SYMBOL diode 848 -496 R0
SYMATTR InstName D8
SYMBOL diode 848 -400 R0
SYMATTR InstName D9
SYMBOL diode 848 -272 R0
SYMATTR InstName D10
SYMBOL pnp 944 368 M180
SYMATTR InstName Q20
SYMBOL res 736 -16 R90
SYMATTR InstName R16
SYMATTR Value 10k
SYMBOL cap 592 288 R90
SYMATTR InstName C1
SYMATTR Value 10pF
SYMBOL diode 512 32 R0
SYMATTR InstName D11
SYMBOL diode 608 96 R180
SYMATTR InstName D12
SYMBOL current -224 672 R0
SYMATTR InstName I1
SYMATTR Value 0.5mA
SYMBOL current -128 672 R0
SYMATTR InstName I2
SYMATTR Value 0.5mA
SYMBOL current 160 672 R0
SYMATTR InstName I3
SYMATTR Value 10mA
SYMBOL current 688 656 R0
SYMATTR InstName I4
SYMATTR Value 5mA
SYMBOL current 432 -384 R0
SYMATTR InstName I5
SYMATTR Value 1mA
SYMBOL npn -192 -128 R0
SYMATTR InstName Q17
SYMATTR Value 2N3904
SYMBOL current 864 -736 R0
SYMATTR InstName I6
SYMATTR Value 10mA
SYMBOL current 224 -672 R0
SYMATTR InstName I7
SYMATTR Value 1mA
SYMBOL res 1392 -16 R90
SYMATTR InstName R19
SYMATTR Value 0.0001
SYMBOL voltage -1456 -320 R0
SYMATTR InstName V1
SYMATTR Value 30
SYMBOL voltage -1456 -176 R0
SYMATTR InstName V2
SYMATTR Value 30
SYMBOL voltage -1216 -160 R0
SYMATTR InstName V3
SYMATTR Value SINE(0 0.2 10k)
SYMBOL res -1200 144 R90
SYMATTR InstName R17
SYMATTR Value 1k
SYMBOL res -1328 352 R180
SYMATTR InstName R18
SYMATTR Value 100
SYMBOL res -1008 160 R0
SYMATTR InstName R20
SYMATTR Value 10k
SYMBOL cap -912 192 R0
SYMATTR InstName C2
SYMATTR Value 1u
SYMBOL res -1200 176 R0
SYMATTR InstName R21
SYMATTR Value 4