* SPICE netlist
Q1 N004 N002 N001 0 2N5401
R1 N001 N002 70
R2 0 N004 226k
R3 N009 N007 10
R4 N007 N010 10
Q3 N014 in N009 0 2N5401
Q4 N016 N011 N010 0 2N5401
Q5 N014 N016 N019 0 2N5550
Q6 N016 N016 N020 0 2N5550
R5 N019 N017 10
R6 N020 N017 10
R7 N011 0 1k
R8 out N011 19k
Q8 N005 N003 N001 0 2N5401
R9 N005 0 75k
R10 N001 N003 23
Q2 N007 N004 N002 0 2N5401
Q7 N006 N005 N003 0 2N5401
Q9 N006 N012 N013 0 2N5550
R11 N006 N012 35
R12 N012 N013 35
Q10 N013 N018 N021 0 2N5550
Q11 0 N014 N018 0 2N5550
Q12 N014 N021 N017 0 2N5550
R13 N021 N017 20
R14 N018 N017 20
Q13 N001 N006 N008 0 2N5550
Q14 N001 N008 out 0 2N3055
Q15 N017 N013 N015 0 2N5401
Q16 N017 N015 out 0 2N5401
V1 N001 0 24
V2 N017 0 -24
V3 in 0 SINE(0 0.7 1k) AC 1
R19 out 0 4
Q17 N001 N008 out 0 2N3055
Q18 N017 N015 out 0 PNP
R15 N008 out 10
R16 out N015 10
C1 N013 N014 20p
.tran 0 4m 1m
.four 1kHz V(in) V(out)

* LTspice schematic (.asc)
Version 4.1
SHEET 1 1856 1520
WIRE -688 -760 -928 -760
WIRE 16 -760 -688 -760
WIRE 560 -760 16 -760
WIRE -928 -728 -928 -760
WIRE -688 -664 -688 -760
WIRE -688 -664 -768 -664
WIRE -624 -664 -688 -664
WIRE 16 -664 16 -760
WIRE 16 -664 -48 -664
WIRE 80 -664 16 -664
WIRE -624 -648 -624 -664
WIRE -928 -632 -928 -648
WIRE 80 -616 80 -664
WIRE -768 -568 -768 -664
WIRE -48 -552 -48 -664
WIRE -624 -520 -624 -568
WIRE -624 -520 -704 -520
WIRE 80 -504 80 -536
WIRE 80 -504 16 -504
WIRE -624 -472 -624 -520
WIRE 80 -472 80 -504
WIRE -768 -424 -768 -472
WIRE -688 -424 -768 -424
WIRE -48 -424 -48 -456
WIRE 16 -424 -48 -424
WIRE -768 -392 -768 -424
WIRE -48 -392 -48 -424
WIRE 560 -376 560 -760
WIRE 560 -376 480 -376
WIRE 640 -376 560 -376
WIRE 800 -376 640 -376
WIRE 480 -344 480 -376
WIRE -768 -296 -768 -312
WIRE 80 -296 80 -376
WIRE 416 -296 80 -296
WIRE -48 -280 -48 -312
WIRE 640 -264 640 -376
WIRE 800 -264 800 -376
WIRE -624 -216 -624 -376
WIRE -624 -216 -704 -216
WIRE -544 -216 -624 -216
WIRE 288 -216 -128 -216
WIRE 480 -216 480 -248
WIRE 576 -216 480 -216
WIRE 736 -216 576 -216
WIRE -704 -184 -704 -216
WIRE -544 -184 -544 -216
WIRE 80 -168 80 -296
WIRE 80 -168 -16 -168
WIRE 80 -152 80 -168
WIRE 480 -152 480 -216
WIRE -704 -72 -704 -104
WIRE -544 -72 -544 -104
WIRE -16 -72 -16 -168
WIRE -768 -24 -928 -24
WIRE -432 -24 -480 -24
WIRE -384 -24 -432 -24
WIRE -128 -24 -128 -216
WIRE -128 -24 -304 -24
WIRE 80 -24 80 -72
WIRE 80 -24 48 -24
WIRE 288 -24 288 -216
WIRE 480 -24 480 -72
WIRE 480 -24 288 -24
WIRE 640 -24 640 -168
WIRE 640 -24 480 -24
WIRE 800 -24 800 -168
WIRE 800 -24 640 -24
WIRE 880 -24 800 -24
WIRE 928 -24 880 -24
WIRE -928 8 -928 -24
WIRE -432 8 -432 -24
WIRE 928 8 928 -24
WIRE 80 24 80 -24
WIRE 480 56 480 -24
WIRE -928 104 -928 88
WIRE 928 104 928 88
WIRE -432 120 -432 88
WIRE -16 120 -16 24
WIRE 80 120 80 104
WIRE 80 120 -16 120
WIRE 640 120 640 -24
WIRE 800 120 800 -24
WIRE -192 168 -272 168
WIRE 80 168 80 120
WIRE 80 168 -128 168
WIRE 480 168 480 136
WIRE 576 168 480 168
WIRE 736 168 576 168
WIRE -704 184 -704 24
WIRE -432 184 -704 184
WIRE 480 200 480 168
WIRE -80 232 -192 232
WIRE 80 248 80 168
WIRE 416 248 80 248
WIRE -544 264 -544 24
WIRE -544 264 -624 264
WIRE -192 264 -192 232
WIRE -80 264 -80 232
WIRE -704 280 -704 184
WIRE -544 280 -544 264
WIRE -432 312 -432 184
WIRE -272 312 -272 168
WIRE -272 312 -432 312
WIRE -192 312 -272 312
WIRE -144 312 -192 312
WIRE 80 312 80 248
WIRE -624 328 -624 264
WIRE -624 328 -640 328
WIRE -608 328 -624 328
WIRE 480 328 480 296
WIRE 560 328 480 328
WIRE 640 328 640 216
WIRE 640 328 560 328
WIRE 800 328 800 216
WIRE 800 328 640 328
WIRE 16 360 -80 360
WIRE -192 376 -192 312
WIRE -704 424 -704 376
WIRE -544 424 -544 376
WIRE 80 424 80 408
WIRE 80 424 -128 424
WIRE -80 440 -80 360
WIRE 80 440 80 424
WIRE -704 536 -704 504
WIRE -624 536 -704 536
WIRE -544 536 -544 504
WIRE -544 536 -624 536
WIRE -192 536 -192 472
WIRE -80 536 -80 520
WIRE -80 536 -192 536
WIRE 80 536 80 520
WIRE 80 536 -80 536
WIRE -624 616 -624 536
WIRE -624 616 -928 616
WIRE -80 616 -80 536
WIRE -80 616 -624 616
WIRE 560 616 560 328
WIRE 560 616 -80 616
WIRE -928 648 -928 616
WIRE -928 760 -928 728
FLAG -768 -296 0
FLAG -432 120 0
FLAG -48 -280 0
FLAG -192 264 0
FLAG -928 -632 0
FLAG -928 760 0
FLAG -928 104 0
FLAG 928 104 0
FLAG 880 -24 out
FLAG -928 -24 in
SYMBOL pnp -704 -472 R180
SYMATTR InstName Q1
SYMATTR Value 2N5401
SYMBOL res -640 -664 R0
SYMATTR InstName R1
SYMATTR Value 70
SYMBOL res -752 -296 R180
SYMATTR InstName R2
SYMATTR Value 226k
SYMBOL res -688 -88 R180
SYMATTR InstName R3
SYMATTR Value 10
SYMBOL res -560 -200 R0
SYMATTR InstName R4
SYMATTR Value 10
SYMBOL pnp -768 24 M180
SYMATTR InstName Q3
SYMATTR Value 2N5401
SYMBOL pnp -480 24 R180
SYMATTR InstName Q4
SYMATTR Value 2N5401
SYMBOL npn -640 280 M0
SYMATTR InstName Q5
SYMATTR Value 2N5550
SYMBOL npn -608 280 R0
SYMATTR InstName Q6
SYMATTR Value 2N5550
SYMBOL res -720 408 R0
SYMATTR InstName R5
SYMATTR Value 10
SYMBOL res -560 408 R0
SYMATTR InstName R6
SYMATTR Value 10
SYMBOL res -448 -8 R0
SYMATTR InstName R7
SYMATTR Value 1k
SYMBOL res -288 -40 R90
SYMATTR InstName R8
SYMATTR Value 19k
SYMBOL pnp 16 -456 R180
SYMATTR InstName Q8
SYMATTR Value 2N5401
SYMBOL res -64 -408 R0
SYMATTR InstName R9
SYMATTR Value 75k
SYMBOL res 64 -632 R0
SYMATTR InstName R10
SYMATTR Value 23
SYMBOL pnp -688 -376 M180
SYMATTR InstName Q2
SYMATTR Value 2N5401
SYMBOL pnp 16 -376 M180
SYMATTR InstName Q7
SYMATTR Value 2N5401
SYMBOL npn 48 -72 M0
SYMATTR InstName Q9
SYMATTR Value 2N5550
SYMBOL res 64 -168 R0
SYMATTR InstName R11
SYMATTR Value 35
SYMBOL res 64 8 R0
SYMATTR InstName R12
SYMATTR Value 35
SYMBOL npn 16 312 R0
SYMATTR InstName Q10
SYMATTR Value 2N5550
SYMBOL npn -144 264 R0
SYMATTR InstName Q11
SYMATTR Value 2N5550
SYMBOL npn -128 376 M0
SYMATTR InstName Q12
SYMATTR Value 2N5550
SYMBOL res 64 424 R0
SYMATTR InstName R13
SYMATTR Value 20
SYMBOL res -96 424 R0
SYMATTR InstName R14
SYMATTR Value 20
SYMBOL npn 416 -344 R0
SYMATTR InstName Q13
SYMATTR Value 2N5550
SYMBOL npn 576 -264 R0
SYMATTR InstName Q14
SYMATTR Value 2N3055
SYMBOL pnp 416 296 M180
SYMATTR InstName Q15
SYMATTR Value 2N5401
SYMBOL pnp 576 216 M180
SYMATTR InstName Q16
SYMATTR Value 2N5401
SYMBOL voltage -928 -744 R0
SYMATTR InstName V1
SYMATTR Value 24
SYMBOL voltage -928 632 R0
SYMATTR InstName V2
SYMATTR Value -24
SYMBOL voltage -928 -8 R0
SYMATTR Value SINE(0 0.7 1k)
SYMATTR Value2 AC 1
SYMATTR InstName V3
SYMBOL res 912 -8 R0
SYMATTR InstName R19
SYMATTR Value 4
SYMBOL npn 736 -264 R0
SYMATTR InstName Q17
SYMATTR Value 2N3055
SYMBOL pnp 736 216 M180
SYMATTR InstName Q18
SYMBOL res 464 -168 R0
SYMATTR InstName R15
SYMATTR Value 10
SYMBOL res 464 40 R0
SYMATTR InstName R16
SYMATTR Value 10
SYMBOL cap -128 152 R90
SYMATTR InstName C1
SYMATTR Value 20p