I paid around 100$ for 5 pcs so I would like to use it as-is. The logic board is manufactured because it was a bit too complex for me to do it (~200 vias) so I cannot modify the electric connections. The whole schematic is built on 2 boards: logic and drivers. Look at the schematic you will see it is very crude as I do not useĪny opamps to offset the voltage drop but only run the DAC over a The controller to continuously sweep them backwards and forwards.Īfter a few days of this treatment they started to behave and have I ran them 50% over current for a few hours and then used They have the primer, I found that initially the tubes struck inĭifferent places and were irratic when trying to sweep a bar across I built a simple "7 segment" clock using IN13 tubes. Send an email to post to this group, send email to view this discussion on the web, visit. To unsubscribe from this group and stop receiving emails from it, You received this message because you are subscribed to the Google I can share the schematic if you want.Ĭan someone still tell me what should be the parameters of the low-pass filter on the driver stage? The beauty of the MCU schematic was that it was scalable so, in theory, you could attach 10-20 tubes with no issue. I was enticed by the idea of having an MCU doing a FFT rather than separate active filters for each band. I also built a spectrum analyzer schematic based on a MCU but that wasn't successful at all I jumped too soon into building it and I don't think it was well thought, well designed or even built. When I will build the PC monitor I will definitely need something small to fit on the back of a PC bay panel (the plastic bay on the front of the PC case). Rectified DC sounds like a better option in terms of results but I think it's too bulky I found a schematic with rectified DC + uplifting diode bridge but I didn't consider it yet. I have multiple projects with Nixies, the spectrum analyzer is the first one and it will be followed by a PC monitor (CPU and MEM). PS: shall I give up on IN-9 and buy IN-13? I read though that it's not guaranteed they will work absolutely fine. For some reason, the voltage reading is not constant, it varies - 145-170V Sometimes they go in the middle but not always.Īny opinions on the above? The HV PSU is digital with MAX1771 not analog with transformer. I ended up with option "b" and the thing is that some work almost fine, and some are firing up from a third from the bottom. how? Is the voltage divider using the low-pass filter resistor for doing this?Įither way, I tried almost all variants in my schematic and none has a definitive and decisive result. The Instructables schematic (see link above) mentioned a voltage divider of the input voltage but. If we go with the RC low pass formula, we get ~160Hz for the given values which I really don"t get what it's forĮ. Question is: do I have to have a low-pass filter tuned for each channel or is one for all? If it's one for all, what should be the cut-off frequency? I found different lox-pass Nixie filters and they were usually built with R=10k ad C=100n. I understood this should fix the IN-9 issue regarding firing up from the bottom. What is its purpose? Does is raise the amplification?ĭ. same as "b" but interestingly, it has a resistor in the op amp's negative reaction loop. same as "a" + a pot for varying the currentĬ. "blind" op amp driver + limiting current resistor - this is in the Nixie documentation so it's the 1st building blockī. Driver stage - I've put together all the op amp driver schematics I found, including the one in the original schematic (Instructables) there are basically 5 variants for which I do have some questionsĪ. My tubes are lit all the way up, just not when they are supposed to. Burn-in - this was new to me - it seems that the tubes must be burned-in prior to using them. I boiled down what I read to the points below:ġ. Well, aside the modifications I made regarding the number of channels and the lin-to-log converter, I have an issue with how the Nixies are lit of course, not all are lit from the bottom and their behavior are somehow erratic. I believe the schematic is very well known, Instructables. I recently bought some IN-9 Nixies from eBay for building a stereo 10-channel spectrum analyzer. Not sure I understood everything so that's why I would like an extensive opinion on this matter. I know there are a lot of discussions on this topic and I believe I read almost everything.
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