You can run nixie tubes at much higher voltages if you wish, it does no harm as long as you increase the series resistor to keep the current within spec. For example, my first nixie clock runs the B5092 tubes from a +340V supply, and I used a larger resistor (75K I think) to get the optimal 2.2mA current. Running at higher voltage gives you more design margin, but it does waste more energy as heat. Generally my HV supplies run between +200 and +220VDC; seems like every clock I make ends-up with a different power supply design. So far, I've designed and built nixie clocks with B5092, B6091, B7971, IN-18, and RZ568m tubes.
I would bump your supply up to +200V, and adjust the resistor to get 8mA of peak current (6:1 multiplexing). That will give plenty of voltage margin as the tubes age. From the photo, 8mA looks nice. I recommend that you view your tube as you vary the supply voltage to get currents between 5mA and 12mA just so you can see the effect of current on brightness. You should see that once the tube is lit "normally", increasing the current doesn't make as much of a change visually. I dont run my tubes multiplexed for a variety of reasons. On Friday, October 27, 2023 at 1:38:06 AM UTC-7 Craig Garnett wrote: > Thanks gregebert > > My HT is a 12V module and is adjustable but the tube spec says 170V so I > left it at that. > Are you saying that it's safe to increase the HT to get maybe 10mA? > > Craig > > On Friday, 27 October 2023 at 05:06:34 UTC+1 gregebert wrote: > >> My concern is that over time as the tubes age your HV supply voltage >> might be too low to ensure proper ionization. If it's not adjustable, you >> can boost it with a series DC supply such as a wall-wart transformer or a >> small isolated DCDC converter. Anything from +12 to +24 should work fine, >> and the current is pretty low (12mA). >> >> Once you get the HV supply resolved, you will be able to get more current >> thru the tubes. BUT......you may want to stay with 8mA. From the photo, the >> tubes glow nicely. Tube wearout is an exponential function of current, so >> staying at the lower currents is better for longer lifetime. At some point, >> the current could be too low and you might see cathode poisoning, but >> that's reversible. My gut feeling is that 8mA of pulsed current should be >> fine. >> >> So, are you using rectified AC-mains as your DC supply ? No worries, I've >> done that on several clocks and it can be done safely with proper circuit >> design. >> >> On Thursday, October 26, 2023 at 7:28:18 AM UTC-7 Craig Garnett wrote: >> >>> The ongoing project of mine is coming on nicely but I need some >>> reassurance with the way I'm driving the Z570s. >>> >>> There are two banks of 6 multiplexed tubes, from what I see from the >>> datasheet these should run at 2ma static or up to 12ma as a 1 in 6 >>> multiplex but that is using google to translate from the datasheet's German. >>> >>> The problem is that even with a 1K anode resistor I can't quite get 8mA >>> from a 170V supply. >>> The photo shows two tubes, the left is static at 2mA and the right is >>> multiplexed at just under 8mA with a 1mS on time from a 170V supply and 1K >>> anode resistor.. >>> >>> Is this ok or could I do it a better way? >>> >>> Thanks >>> Craig >>> >> -- 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 [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/f943702e-f2fc-430b-ad0d-bae959ef391fn%40googlegroups.com.
