* SPICE netlist
Q1 N008 N005 N014 0 NPN
Q2 N008 N005 N003 0 PNP
R1 N014 N016 15k
R2 N001 N003 15k
V1 N001 0 15
V2 N016 0 -15
R3 N005 0 22k
R4 N005 N007 22k
V3 N007 0 SINE(0 {Vval} 440)
R5 N009 0 10k
C1 N009 N008 1
XU1 N013 N009 N010 opamp Aol=100K GBW=10Meg ;pnba invin)noninvin)out
Q3 N011 N006 N015 0 NPN
Q4 N011 N006 N004 0 PNP
R6 N015 N017 15k
R7 N002 N004 15k
V4 N002 0 15
V5 N017 0 -15
R8 N006 0 22k
R9 N006 N010 22k
R10 N012 0 10k
C2 N012 N011 1
R11 N010 N013 10k
R12 0 N013 1k
.tran 10ms
.step dec param Vval 0.05 5 2

* LTspice schematic (.asc)
Version 4
SHEET 1 1024 592
WIRE -304 -296 -384 -296
WIRE -384 -280 -384 -296
WIRE -304 -280 -304 -296
WIRE 336 -280 256 -280
WIRE 256 -264 256 -280
WIRE 336 -264 336 -280
WIRE -384 -184 -384 -200
WIRE -304 -168 -304 -200
WIRE 256 -168 256 -184
WIRE 336 -152 336 -184
WIRE -368 -120 -400 -120
WIRE 272 -104 240 -104
WIRE -496 -56 -512 -56
WIRE -400 -56 -400 -120
WIRE -400 -56 -416 -56
WIRE -304 -56 -304 -72
WIRE -256 -56 -304 -56
WIRE -128 -56 -192 -56
WIRE 32 -56 -128 -56
WIRE -512 -40 -512 -56
WIRE -304 -40 -304 -56
WIRE -128 -40 -128 -56
WIRE 128 -40 96 -40
WIRE 144 -40 128 -40
WIRE 240 -40 240 -104
WIRE 240 -40 224 -40
WIRE 336 -40 336 -56
WIRE 384 -40 336 -40
WIRE 512 -40 448 -40
WIRE 32 -24 16 -24
WIRE 336 -24 336 -40
WIRE 512 -24 512 -40
WIRE -400 8 -400 -56
WIRE -368 8 -400 8
WIRE -400 24 -400 8
WIRE 240 24 240 -40
WIRE 272 24 240 24
WIRE 16 40 16 -24
WIRE 32 40 16 40
WIRE 128 40 128 -40
WIRE 128 40 112 40
WIRE 240 40 240 24
WIRE -512 56 -512 40
WIRE -128 56 -128 40
WIRE 16 56 16 40
WIRE 512 72 512 56
WIRE -304 88 -304 56
WIRE 336 104 336 72
WIRE -400 120 -400 104
WIRE 240 136 240 120
WIRE 16 152 16 136
WIRE -304 184 -304 168
WIRE 336 200 336 184
WIRE -304 280 -304 264
WIRE 336 296 336 280
FLAG -384 -184 0
FLAG -304 280 0
FLAG -400 120 0
FLAG -512 56 0
FLAG -128 56 0
FLAG 256 -168 0
FLAG 336 296 0
FLAG 240 136 0
FLAG 512 72 0
FLAG 16 152 0
SYMBOL npn -368 -40 R0
SYMATTR InstName Q1
SYMBOL pnp -368 -72 M180
SYMATTR InstName Q2
SYMBOL res -320 72 R0
SYMATTR InstName R1
SYMATTR Value 15k
SYMBOL res -320 -296 R0
SYMATTR InstName R2
SYMATTR Value 15k
SYMBOL voltage -384 -296 M0
SYMATTR InstName V1
SYMATTR Value 15
SYMBOL voltage -304 168 M0
SYMATTR InstName V2
SYMATTR Value -15
SYMBOL res -384 8 M0
SYMATTR InstName R3
SYMATTR Value 22k
SYMBOL res -400 -40 M270
SYMATTR InstName R4
SYMATTR Value 22k
SYMBOL voltage -512 -56 M0
SYMATTR InstName V3
SYMATTR Value SINE(0 {Vval} 440)
SYMBOL res -144 -56 R0
SYMATTR InstName R5
SYMATTR Value 10k
SYMBOL cap -192 -72 R90
SYMATTR InstName C1
SYMATTR Value 1
SYMBOL Opamps\\opamp 64 24 M180
SYMATTR InstName U1
SYMBOL npn 272 -24 R0
SYMATTR InstName Q3
SYMBOL pnp 272 -56 M180
SYMATTR InstName Q4
SYMBOL res 320 88 R0
SYMATTR InstName R6
SYMATTR Value 15k
SYMBOL res 320 -280 R0
SYMATTR InstName R7
SYMATTR Value 15k
SYMBOL voltage 256 -280 M0
SYMATTR InstName V4
SYMATTR Value 15
SYMBOL voltage 336 184 M0
SYMATTR InstName V5
SYMATTR Value -15
SYMBOL res 256 24 M0
SYMATTR InstName R8
SYMATTR Value 22k
SYMBOL res 240 -24 M270
SYMATTR InstName R9
SYMATTR Value 22k
SYMBOL res 496 -40 R0
SYMATTR InstName R10
SYMATTR Value 10k
SYMBOL cap 448 -56 R90
SYMATTR InstName C2
SYMATTR Value 1
SYMBOL res 128 24 R90
SYMATTR InstName R11
SYMATTR Value 10k
SYMBOL res 32 152 R180
SYMATTR InstName R12
SYMATTR Value 1k