There's a big difference between the Russian sockets and the Burroughs sockets - the Russian sockets have a two prong grip (like two prongs on a fork) on the pin which is a lot more unforgiving compared to the funnel (tube) type on the Burroughs sockets. In the Burroughs sockets this funnel moves freely in all directions, in the Russian socket these two prongs only move along the slit they sit in and they don't give as much as the Burroughs type do.
If you can't get hold of the proper socket use loose pins and bend them slightly if needed. /Martin On Thursday, 7 August 2025 at 08:58:47 UTC+2 Michail Wilson wrote: > It depends on who you ask. The sockets have floating pin connectors. > I’ve used them interchangeably for years without issue. > > > > B-5991 datasheet says to use socket SK-136 (PL31A-P) > > IN-12 says to use socket SK-144 > > > > > https://www.tube-tester.com/sites/nixie/data/soc/SK-136-14pin-chas/SK-136-14pin-ch.htm > > > > > > M1 > > > > *From:* [email protected] <[email protected]> *On Behalf > Of *Leroy Jones > *Sent:* Wednesday, August 6, 2025 2:57 PM > *To:* neonixie-l <[email protected]> > *Subject:* Re: [neonixie-l] Re: Newcomer From Asheville, NC 5991 vs IN-12 > > > > Absolutely correct! The Russian tubes are metric. The USA tubes are > in inches. Close but not an exact match. > > Using the incorrect socket puts a stress on the pins and will crack the > glass. The glass seals around the pins are by far the > > most delicate part of a tube. Avoid heat and mechanical stress on tube > pins. I have learned this the hard way over the past 40 years! > > > > > > On Wednesday, August 6, 2025 at 5:16:21 PM UTC-4 Dekatron42 wrote: > > There are slight differences between the B5991/2 and the IN-12A/B pin > spacing according to datashets, dimensions can be found here: > > > > IN-12: IN-12A_IN-12B_03.pdf > <https://www.tube-tester.com/sites/nixie/dat_arch/IN-12A_IN-12B_03.pdf> > > > > B5991: https://frank.pocnet.net/sheets/116/b/B5991.pdf > > > > Overall dimensions is in inches on the B5991 and millimeter on the IN-12 > which makes the two tubes almost fit in each others sockets. The sockets > I've tested puts a lot of strain on the pins possibly leading to cracks in > the seals of the tube pins if pressed in to hard, either directly or over > time. The Burroughs type has a total lengthwise distance of 0.68 inches > whoch si close to 17.3mm whereas the IN-12 is specified at 18mm, the other > direction the Burroughs types is 11.2mm whereas the IN-12 is 11.5 (not much > of a difference) but the other way it is almost 0.7mm which is quite a lot. > > > > Neither do I recommend cutting off pins on Nixie tubes as that will > probably lead to cracks in the seal, there are flying lead Nixies like the > B5750 or IN-16 and even on those you shouldn't cut the pins to close to the > glass seal nor should you solder to close to the glass seal as the high > temperature from the soldering iron might lead to cracks as the pins expand > in the glass seal. > > > > Since I discovered this difference I've always used the correct sockets > for the specified Nixie, or used single pins. > > > > /Martin > > > > > > > > On Wednesday, 6 August 2025 at 01:37:28 UTC+2 Michail Wilson wrote: > > Hello, > > > > Pin 13 and 14 are not used. Most sockets (if not all) will have an open > area for the pins to slide in even if no connection is made. For that > tube, you could literally simply cut them down (carefully) so you don’t > have to worry about it like in the circuit design you included a picture of > (pcbway?). > > > > Very few tubes use those pins (like the B5971) so finding the sockets > loaded with all 14 holes is rare in itself. When I spot them on ebay, I > snag them (for no real reason other than just knowing they’re rare). I > love the auctions where people post pictures of tubes with sockets (14 pin > complete) and selling for the cost of a $5-$10 tube. Those sockets are > worth more than the tube itself. > > > > I believe the 5991 is pin compatible with the IN-12 (That is IN-12A. > The IN-12B uses pin 12 for the leading decimal point where the 5991 and > IN-12A don’t have it. > > > > (So, unless you’re using a B5971, you don’t need sockets with pin 13/14 > loaded with connecting gear) > > > > M1 > > > > *From:* [email protected] <[email protected]> *On Behalf > Of *Tom Lang > *Sent:* Sunday, August 3, 2025 9:45 AM > *To:* neonixie-l <[email protected]> > *Subject:* [neonixie-l] Re: Newcomer From Asheville, NC 5991 vs IN-12 > > > > Some insight as I was thinking about this. I looked at some pcb sockets. > Apparently pins 13 and 14 are not carried thru the actual socket itself. > This would imply that as long as the tubes were not directly soldered onto > the pcb board itself (I would expect no one to do this) a board for the > IN-12 could accommodate a 5991 after all?? > > On Sunday, August 3, 2025 at 12:35:37 PM UTC-4 Tom Lang wrote: > > I'm a retired electrical engineer familiar with designing and building > vacuum tube amplifiers. This is my first foray into the nixie tube clock > world. > > > > I want to use the Burroughs 5991 tube on some pcb boards designed for the > IN-12 tube. I have looked and looked but cannot find definitive answers as > to physical interchangeability of the two especially on prefabricated pcb > boards designed for the IN-12. At this time I do not have any of the tubes > or boards on hand. > > > > It appears (see attachments) that the 5991 has two extra pins 13 & 14 that > would have to be accommodated if one were to utilize a 5991 on a board for > the IN-12. However, the picture of the "tube adapters" implies otherwise > (where's the holes for 13 and 14?). Also it DOES appear that chassis mount > sockets (such as the brown ones shown) do have relief holes for the extra > 5991 pins. > > > > There are attractive prices for premade boards for the IN-12 tubes that I > probably would purchase if they are compatible with the 5991. However, I > don't mind having to use chassis mounted sockets and flying leads if > necessary for the 5991. > > > > Thanks for your help. > > -- > 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, visit > https://groups.google.com/d/msgid/neonixie-l/f5f96fac-3906-4457-996d-54749fd39815n%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/f5f96fac-3906-4457-996d-54749fd39815n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > 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, visit > https://groups.google.com/d/msgid/neonixie-l/4df433e6-34c7-4dc0-9265-d718acbbc8e4n%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/4df433e6-34c7-4dc0-9265-d718acbbc8e4n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- 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, visit https://groups.google.com/d/msgid/neonixie-l/7dbf4272-572b-4924-97c2-29fa9fcb97fdn%40googlegroups.com.
