The simulation of the 555 circuit is in the attachment; I got this schematic/option from the Instructables author himself after I told him that 2 Quad comparators per channel is overkill. The schematic came with 2 issues which I didn't pay attention to check: 1. the type of the 555 circuit itself - I can't quite figure out what it is - looks like an astable but it's not quite there 2. the transistor's base resistor - in his original schematic this resistor was only 10K. Well, it seems that even LTSpice is having its bad days because, taken into consideration the other surrounding parameters, the schematic doesn't work in practice even though Spice says it's possible. If the base resistor is under 68-100k then the voltage of the function generator is greater than the audio input (as I said in one of my previous messages). If you look at the schematic you will see that the output of the wave gen is connected to the inverting input of the comparator; well, considering the audio voltage ~3V and the wave gen ~ 8V then the result is quite clear - no signal at the comparator's output. I had to increase the base resistor to over 68k so I can get the desired result.
PS: the PSU has a 4.7uF/250 at the HV output; shall I lower it or even remove it? -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/ca80fef7-6ff6-4c37-9d02-58019ee10bc7%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Version 4
SHEET 1 1608 680
WIRE 112 -448 -400 -448
WIRE 480 -448 112 -448
WIRE 832 -448 480 -448
WIRE 1056 -448 832 -448
WIRE -400 -336 -400 -448
WIRE -192 -336 -400 -336
WIRE 512 -304 304 -304
WIRE 832 -304 832 -448
WIRE 832 -304 736 -304
WIRE -400 -288 -400 -336
WIRE 304 -272 304 -304
WIRE 512 -240 448 -240
WIRE 800 -240 736 -240
WIRE 912 -240 880 -240
WIRE -592 -224 -624 -224
WIRE 112 -224 112 -448
WIRE -192 -176 -192 -336
WIRE 240 -176 176 -176
WIRE 384 -176 320 -176
WIRE 512 -176 384 -176
WIRE 800 -176 736 -176
WIRE 912 -176 912 -240
WIRE 912 -176 800 -176
WIRE 0 -160 -160 -160
WIRE 1056 -160 1056 -448
WIRE -624 -144 -624 -224
WIRE -576 -144 -624 -144
WIRE -512 -144 -576 -144
WIRE -400 -144 -400 -208
WIRE -400 -144 -432 -144
WIRE -224 -144 -400 -144
WIRE -128 -128 -160 -128
WIRE 0 -128 0 -160
WIRE 64 -128 0 -128
WIRE 112 -128 64 -128
WIRE -576 -112 -576 -144
WIRE 480 -112 480 -448
WIRE 512 -112 480 -112
WIRE 768 -112 736 -112
WIRE 0 -48 0 -128
WIRE 64 -48 64 -128
WIRE -128 -32 -128 -128
WIRE 448 -32 448 -240
WIRE 800 -32 800 -176
WIRE 800 -32 448 -32
WIRE 1056 -32 1056 -80
WIRE 384 0 384 -176
WIRE 576 0 384 0
WIRE 912 0 912 -176
WIRE 912 0 656 0
WIRE -192 16 -192 -112
WIRE 768 16 768 -112
WIRE 912 16 912 0
WIRE -576 48 -576 -48
WIRE 0 64 0 32
WIRE 32 64 0 64
WIRE 64 64 64 16
WIRE 64 64 32 64
WIRE -128 80 -128 48
WIRE 32 144 32 64
WIRE 768 144 768 80
WIRE 912 144 912 80
FLAG 304 -272 0
FLAG 768 144 0
FLAG 912 144 0
FLAG 32 144 0
FLAG 1056 -32 0
FLAG -128 80 0
FLAG -576 48 0
FLAG -192 16 0
FLAG -592 -224 Out
IOPIN -592 -224 Out
SYMBOL Misc\\NE555 624 -208 R0
SYMATTR InstName U1
SYMBOL cap 752 16 R0
SYMATTR InstName C1
SYMATTR Value 0.1µ
SYMBOL res 896 -256 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value {R555/100}
SYMBOL res 672 -16 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value {R555}
SYMBOL res 336 -192 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 68k
SYMBOL res 16 48 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R4
SYMATTR Value 510
SYMBOL cap 896 16 R0
SYMATTR InstName C2
SYMATTR Value 0.1µ
SYMBOL pnp 176 -128 R180
SYMATTR InstName Q1
SYMATTR Value 2N3906
SYMBOL cap 48 -48 R0
SYMATTR InstName C3
SYMATTR Value 0.1µ
SYMBOL voltage 1056 -176 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL voltage -128 -48 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value PULSE(0 3 0 0.5 1p 1p 0.002)
SYMBOL res -384 -192 R180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R5
SYMATTR Value 6.8k
SYMBOL res -416 -160 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R6
SYMATTR Value 100k
SYMBOL cap -592 -112 R0
SYMATTR InstName C4
SYMATTR Value 1µ
SYMBOL Comparators\\LT1018 -192 -144 M0
SYMATTR InstName U2
TEXT -648 168 Left 2 !.tran 0 0.5 0 0.01m
TEXT 1184 -368 Left 2 !.param f555=5000
TEXT 1184 -336 Left 2 !.param C555=0.1u
TEXT 1192 -304 Left 2 !.param R555={1/(0.7*f555*C555)}
TEXT 224 48 Left 2 !.param Cexp=0.1u
TEXT 224 72 Left 2 !.param dbGain=0.25
TEXT 224 104 Left 2 !.param Rexp={dbGain/(f555*Cexp)}
