Re: 80dB now but still needs improvement at 1KHz

"Liz Tuddenham" <liz@poppyrecords.invalid.invalid> wrote in message news:1r37pyc.1bodve2fz5t4wN%liz@poppyrecords.invalid.invalid...

Edward Rawde <invalid@invalid.invalid> wrote:
>
[...]
>

Now approacing 90dB if you believe the simulation with with this
experimental circuit. > You'll want to find something else to do while
it simulates.
How to inprove it further?

>
At 1 Kc/s, a distortion figure of 90dB represents one cycle in 10^9, so
you would have to run it for 1000 seconds before the startup transient
became insignificant.

The startup transient was not included in the FFT but in any case the circuit has other issues so here is a circuit which works as
intended.
Harmonics are approaching 100dB down and 1k c/s is below 90dB.
Simulate overnight then stop. It will be at about 250 seconds.
Select roughly the last 50 seconds and FFT on current zoom extent.
Number of data points may need increasing.

What reality would say is anybody's guess and it has been pointed out that real measurements 100dB down may not be meaningful.

We could probably have a discussion here about why c/s is better than Hz

Version 4
SHEET 1 2196 932
WIRE -64 -576 -96 -576
WIRE 48 -576 16 -576
WIRE 128 -528 112 -528
WIRE 208 -528 192 -528
WIRE 288 -528 272 -528
WIRE 368 -528 352 -528
WIRE 448 -528 432 -528
WIRE 528 -528 512 -528
WIRE 640 -528 592 -528
WIRE 640 -512 640 -528
WIRE -32 -464 -32 -480
WIRE 48 -448 48 -576
WIRE 48 -448 0 -448
WIRE -96 -432 -96 -576
WIRE -64 -432 -96 -432
WIRE 112 -416 112 -528
WIRE 112 -416 0 -416
WIRE 160 -416 112 -416
WIRE 208 -416 160 -416
WIRE 336 -416 288 -416
WIRE 400 -416 336 -416
WIRE 512 -416 400 -416
WIRE 624 -416 512 -416
WIRE -96 -384 -96 -432
WIRE -32 -384 -32 -400
WIRE 48 -368 48 -448
WIRE 336 -368 336 -416
WIRE 160 -352 160 -416
WIRE 400 -352 400 -416
WIRE 512 -288 512 -416
WIRE 624 -288 624 -416
WIRE -96 -272 -96 -304
WIRE -96 -272 -192 -272
WIRE -96 -240 -96 -272
WIRE 48 -240 48 -288
WIRE 160 -240 160 -288
WIRE 336 -240 336 -288
WIRE 400 -240 400 -288
WIRE -192 -176 -192 -272
WIRE -224 -128 -256 -128
WIRE -96 -128 -96 -160
WIRE -96 -128 -128 -128
WIRE -80 -128 -96 -128
WIRE 144 -128 -80 -128
WIRE 288 -128 224 -128
WIRE 352 -128 288 -128
WIRE 512 -128 512 -224
WIRE 512 -128 432 -128
WIRE -256 -48 -256 -128
WIRE -208 -48 -256 -48
WIRE -80 -48 -80 -128
WIRE -80 -48 -128 -48
WIRE 288 -16 288 -128
WIRE 288 -16 64 -16
WIRE 352 -16 288 -16
WIRE 512 -16 512 -128
WIRE 512 -16 432 -16
WIRE -256 0 -256 -48
WIRE 144 48 144 32
WIRE -272 96 -352 96
WIRE -208 96 -272 96
WIRE 64 96 64 -16
WIRE 112 96 64 96
WIRE 512 96 512 -16
WIRE 512 96 272 96
WIRE -32 128 -96 128
WIRE 112 128 -32 128
WIRE -352 144 -352 96
WIRE 624 144 624 -224
WIRE 656 144 624 144
WIRE 752 144 720 144
WIRE -208 160 -208 96
WIRE -32 160 -32 128
WIRE 112 160 64 160
WIRE 624 160 624 144
WIRE 624 160 272 160
WIRE 752 176 752 144
WIRE 144 224 144 208
WIRE -32 256 -32 224
WIRE 64 272 64 160
WIRE 160 272 64 272
WIRE 288 272 160 272
WIRE 400 272 352 272
WIRE 512 272 512 96
WIRE 512 272 480 272
WIRE 64 288 64 272
WIRE 160 288 160 272
WIRE 752 288 752 256
WIRE 880 288 752 288
WIRE 928 288 880 288
WIRE -352 320 -352 224
WIRE -352 320 -432 320
WIRE 928 320 928 288
WIRE -432 336 -432 320
WIRE -352 336 -352 320
WIRE -208 336 -208 224
WIRE -208 336 -352 336
WIRE -96 336 -96 128
WIRE 64 384 64 368
WIRE 160 384 160 352
WIRE 160 384 64 384
WIRE -352 416 -352 336
WIRE 64 416 64 384
WIRE -208 432 -208 336
WIRE 192 432 144 432
WIRE 304 432 272 432
WIRE 384 432 368 432
WIRE 928 432 928 400
WIRE 512 448 512 272
WIRE 624 448 624 160
WIRE 288 544 288 528
WIRE 384 560 384 432
WIRE 384 560 320 560
WIRE 624 560 624 512
WIRE 624 560 384 560
WIRE -96 576 -96 416
WIRE -48 576 -96 576
WIRE 32 576 -48 576
WIRE 144 576 144 432
WIRE 144 576 112 576
WIRE 192 576 144 576
WIRE 256 576 192 576
WIRE -352 592 -352 496
WIRE -272 592 -352 592
WIRE -208 592 -208 496
WIRE -208 592 -272 592
WIRE 432 592 320 592
WIRE 512 592 512 512
WIRE 512 592 432 592
WIRE 624 592 624 560
WIRE 704 592 624 592
WIRE -96 624 -96 576
WIRE -48 624 -48 576
WIRE 288 624 288 608
WIRE 512 624 512 592
WIRE 704 624 704 592
WIRE 432 640 432 592
WIRE 624 640 624 592
WIRE -96 736 -96 688
WIRE -48 736 -48 688
WIRE -48 736 -96 736
WIRE 432 736 432 704
WIRE 512 736 512 704
WIRE 512 736 432 736
WIRE 624 736 624 704
WIRE 624 736 512 736
WIRE 704 736 704 704
WIRE 704 736 624 736
WIRE -96 768 -96 736
WIRE 432 768 432 736
FLAG -432 336 0
FLAG 288 528 V+
FLAG 144 224 V-
FLAG -272 96 V+
FLAG -272 592 V-
FLAG 880 288 output
FLAG 144 32 V+
FLAG 288 624 V-
FLAG 432 768 0
FLAG -32 256 0
FLAG -32 -480 V+
FLAG -32 -384 V-
FLAG -256 0 0
FLAG 400 -240 0
FLAG 160 -240 0
FLAG 64 416 0
FLAG 336 -240 0
FLAG -96 768 0
FLAG 192 576 dc-trim
FLAG 640 -512 0
FLAG 48 -240 0
FLAG 928 432 0
SYMBOL voltage -352 128 R0
WINDOW 123 0 0 Left 0
WINDOW 39 10 135 Left 2
WINDOW 0 12 7 Left 2
WINDOW 3 15 104 Left 2
SYMATTR SpiceLine Rser=0.01
SYMATTR InstName V1
SYMATTR Value 6
SYMBOL res 496 256 R90
WINDOW 0 1 52 VBottom 2
WINDOW 3 33 45 VTop 2
SYMATTR InstName R11
SYMATTR Value 10.5k
SYMBOL cap 352 256 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 35 30 VTop 2
SYMATTR InstName C8
SYMATTR Value 15n
SYMATTR SpiceLine V=16 Irms=271m Rser=0.594318 Lser=0 mfg="KEMET" pn="C0603C153K4RAC" type="X7R"
SYMBOL res 240 -144 R90
WINDOW 0 -1 46 VBottom 2
WINDOW 3 35 56 VTop 2
SYMATTR InstName R7
SYMATTR Value 6.34k
SYMBOL res 448 -144 R90
WINDOW 0 -4 61 VBottom 2
WINDOW 3 39 55 VTop 2
SYMATTR InstName R8
SYMATTR Value 13k
SYMBOL njf -128 -176 R90
WINDOW 0 -37 23 VRight 2
WINDOW 3 -9 -3 VRight 2
SYMATTR InstName J1
SYMATTR Value J112
SYMBOL voltage -352 400 R0
WINDOW 123 0 0 Left 0
WINDOW 39 10 135 Left 2
WINDOW 0 10 0 Left 2
WINDOW 3 15 104 Left 2
SYMATTR SpiceLine Rser=0.01
SYMATTR InstName V2
SYMATTR Value 6
SYMBOL res 48 272 R0
WINDOW 3 36 65 Left 2
SYMATTR Value 10.5k
SYMATTR InstName R10
SYMBOL schottky 496 -288 R0
WINDOW 3 -17 -26 VRight 2
SYMATTR Value BAS40HY
SYMATTR InstName D1
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res -112 -64 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 82
SYMBOL OpAmps\LT1994 176 128 R0
WINDOW 3 10 -65 Left 2
WINDOW 0 11 -95 Left 2
SYMATTR InstName U1
SYMBOL schottky 528 448 M0
WINDOW 3 52 -26 VRight 2
WINDOW 0 -18 3 Left 2
SYMATTR Value BAS40HY
SYMATTR InstName D3
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL schottky 640 448 M0
WINDOW 3 49 -26 VRight 2
WINDOW 0 -21 4 Left 2
SYMATTR Value BAS40HY
SYMATTR InstName D4
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 528 608 M0
WINDOW 3 25 87 Left 2
SYMATTR Value 220k
SYMATTR InstName R16
SYMBOL res 720 608 M0
WINDOW 3 27 87 Left 2
SYMATTR Value 220k
SYMATTR InstName R17
SYMBOL res -112 -256 R0
WINDOW 0 38 42 Left 2
WINDOW 3 36 66 Left 2
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL res 320 -384 R0
WINDOW 0 -50 69 Left 2
WINDOW 3 -54 98 Left 2
SYMATTR InstName R13
SYMATTR Value 220k
SYMBOL res 448 -32 R90
WINDOW 0 -4 61 VBottom 2
WINDOW 3 39 55 VTop 2
SYMATTR InstName R9
SYMATTR Value 1.07Meg
SYMBOL res -80 -288 R180
WINDOW 0 40 70 Left 2
WINDOW 3 45 42 Left 2
SYMATTR InstName R1
SYMATTR Value 1k
SYMBOL res -80 432 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R5
SYMATTR Value 33k
SYMBOL res 176 416 M90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R15
SYMATTR Value 220
SYMBOL res 16 560 M90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R14
SYMATTR Value 10k
SYMBOL cap 176 352 R180
WINDOW 0 -37 41 Left 2
WINDOW 3 -50 13 Left 2
SYMATTR InstName C7
SYMATTR Value 15n
SYMATTR SpiceLine V=16 Irms=271m Rser=0.594318 Lser=0 mfg="KEMET" pn="C0603C153K4RAC" type="X7R"
SYMBOL cap 720 128 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C13
SYMATTR Value 100000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0.002 Lser=0 mfg="TDK" pn="C575OX5ROJI07M" type="X5R"
SYMBOL res 736 160 R0
SYMATTR InstName R18
SYMATTR Value 600
SYMBOL res 192 -400 R270
WINDOW 0 35 55 VTop 2
WINDOW 3 -6 55 VBottom 2
SYMATTR InstName R12
SYMATTR Value 220k
SYMBOL cap 176 -352 M0
WINDOW 0 -22 9 Left 2
WINDOW 3 -75 48 Left 2
SYMATTR InstName C6
SYMATTR Value 10000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM155R60J106ME15" type="X5R"
SYMBOL cap 416 -352 M0
WINDOW 0 -32 51 Left 2
WINDOW 3 -72 7 Left 2
SYMATTR InstName C10
SYMATTR Value 10000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM155R60J106ME15" type="X5R"
SYMBOL cap 368 448 M270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName C9
SYMATTR Value 10000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM155R60J106ME15" type="X5R"
SYMBOL cap 416 640 R0
WINDOW 0 -37 6 Left 2
WINDOW 3 -77 53 Left 2
SYMATTR InstName C11
SYMATTR Value 10000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM155R60J106ME15" type="X5R"
SYMBOL cap 608 640 R0
WINDOW 0 -33 9 Left 2
WINDOW 3 -72 51 Left 2
SYMATTR InstName C12
SYMATTR Value 10000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM155R60J106ME15" type="X5R"
SYMBOL cap -224 160 R0
WINDOW 0 -22 9 Left 2
WINDOW 3 -79 48 Left 2
SYMATTR InstName C1
SYMATTR Value 10000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM155R60J106ME15" type="X5R"
SYMBOL cap -224 432 R0
WINDOW 0 -22 9 Left 2
WINDOW 3 -75 50 Left 2
SYMATTR InstName C2
SYMATTR Value 10000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM155R60J106ME15" type="X5R"
SYMBOL cap -16 224 R180
WINDOW 0 23 78 Left 2
WINDOW 3 -74 78 Left 2
SYMATTR InstName C4
SYMATTR Value 10000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM155R60J106ME15" type="X5R"
SYMBOL diode -80 688 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D5
SYMATTR Value 1N4148
SYMBOL cap -64 688 M180
WINDOW 0 24 56 Left 2
WINDOW 3 24 8 Left 2
SYMATTR InstName C5
SYMATTR Value 1000n
SYMATTR SpiceLine V=6.3 Irms=0 Rser=0 Lser=0 mfg="Murata" pn="GRM032R60J105ME05" type="X5R"
SYMBOL OpAmps\LT1678 -32 -432 M0
WINDOW 0 -57 50 Left 2
WINDOW 3 -47 89 Left 2
SYMATTR InstName U2A
SYMBOL diode 192 -544 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D6
SYMATTR Value 1N4148
SYMBOL diode 272 -544 R90
WINDOW 0 58 31 VBottom 2
WINDOW 3 -28 34 VTop 2
SYMATTR InstName D7
SYMATTR Value 1N4148
SYMBOL diode 352 -544 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D8
SYMATTR Value 1N4148
SYMBOL diode 432 -544 R90
WINDOW 0 58 27 VBottom 2
WINDOW 3 -27 31 VTop 2
SYMATTR InstName D9
SYMATTR Value 1N4148
SYMBOL diode 512 -544 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D10
SYMATTR Value 1N4148
SYMBOL schottky 608 -288 R0
WINDOW 3 -16 -25 VRight 2
SYMATTR Value BAS40HY
SYMATTR InstName D2
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res -80 -560 R270
WINDOW 0 33 55 VTop 2
WINDOW 3 -3 55 VBottom 2
SYMATTR InstName R4
SYMATTR Value 10k
SYMBOL res 32 -384 R0
SYMATTR InstName R6
SYMATTR Value 10k
SYMBOL diode 592 -544 R90
WINDOW 0 59 29 VBottom 2
WINDOW 3 -25 30 VTop 2
SYMATTR InstName D11
SYMATTR Value 1N4148
SYMBOL res 912 304 R0
SYMATTR InstName R19
SYMATTR Value 600
SYMBOL OpAmps\LT1678 288 576 M0
WINDOW 0 21 -42 Left 2
WINDOW 3 25 24 Left 2
SYMATTR InstName U2B
TEXT -448 632 Left 2 !.tran 0 1050s 50s startup