Or me? Well, the MJE340 is in a larger package, but other than that, nothing. What Terry said, though, is that the IN-9 requires a MJE340, not a MPSA42 because you need to sink more current. As far as I can tell, 10mA is well within the current handling capabilities of both transistors, so it is interesting that all the designs for the IN-9 use the MJE340, whereas all the designs for regular nixies use the MPSA42.
I happen to have an IN-9 spectrum analyzer sitting on a breadboard that uses the MJE340. I swapped them out for MPSA42 and the results definitely aren’t as good. To stick the glow to the bottom I periodically pull the base to ground - so turning the tubes off. With the MJE340 this works fine. With the MPSA42, not so much. So either they aren’t turning off fully, or they aren’t responding fast enough. Temperature-wise, they were barely above ambient. YMMV. From: Mac Doktor Sent: Wednesday, April 22, 2020 9:16 PM To: neonixie-l Subject: Re: [neonixie-l] MPSA42 or MJE340? On Apr 22, 2020, at 9:03 PM, '[email protected]' via neonixie-l <[email protected]> wrote: What do you have against the MJE340? Me? Nothing. All of the IN-9 projects that I've seen online use the MJE340. I'm a duffer and I'm here to learn. Paul wanted everyone to pile on so have at it! I'd be glad to hear more. Terry Bowman, KA4HJH "The Mac Doctor” "Never install version point-zero of anything" -- You received this message because you are subscribed to a topic in the Google Groups "neonixie-l" group. To unsubscribe from this topic, visit https://groups.google.com/d/topic/neonixie-l/_TX-Z5A27JQ/unsubscribe. To unsubscribe from this group and all its topics, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/33F621FB-E6D6-42FB-AC61-146B81CAC0A7%40gmail.com. -- 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/3CAE9AAB-FD17-41EE-852F-2D30477F6B7F%40gmail.com.
