I have one of the pin top tubes (https://n2jtx.com/NixieClock/Used%20Burroughs%20B-7971.jpg). Unlike most of my other tubes, it is a Burroughs branded tube and not Ultronics. The only thing I ever noticed different about it was it seemed to have a deeper red glow than the Ultronics tubes which are more orange. Perhaps a different amount of mercury in it. Someday when I think about it I'll test it again.
On Wednesday, July 5, 2023 at 3:50:55 AM UTC-4 Jeff Walton wrote: > I have a number of these "rare pin-top" B-7971's and do not find any > significant difference in contrast with the Ultronics versions of the 7971s > . The pin-topped or "antenna top" construction is an early format that > uses a wired backplane instead of the PCB style interconnect. It's a nice > tube that looks good as a group in any clock. There is no practical > difference in operation or appearance and there are certainly some MOD-6 > clock owners that have full sets of these tubes in operation will tell you > that they are equally reliable. They will have date codes in the > mid-1960s. > > It is uncommon to see a group like this available. $250 to $275 each per > tube seems to be the going price on ebay these days. Overpriced but worth > whatever someone is willing to pay. > > My first tubes were $8/pair from Buckbee-Mears and Polypaks back in the > early 1970's and included the boards with each pair. > > Jeff > > -------- Original message -------- > From: Robert <[email protected]> > Date: 7/5/23 2:11 AM (GMT-06:00) > To: [email protected] > Subject: [neonixie-l] B7971 - better contrast > > Not my auction but I saw this > https://www.ebay.co.uk/itm/266322565516?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=v3sg3SvYRJa&sssrc=4429486&ssuid=U1YeAcPgQ5y&var=&widget_ver=artemis&media=COPY > > In the description it says “This sale is for lots of "Pin-Top" version of > the B-7971. The rare "Pin-Top" versions are made with a darker background > on the segments that provide better contrast.” > > I have some of these but have never noticed this > > > Rob > > -- > 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/A272F92E-A09A-48E8-A051-2C15C292A57F%40gmail.com > > <https://groups.google.com/d/msgid/neonixie-l/A272F92E-A09A-48E8-A051-2C15C292A57F%40gmail.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 on the web, visit https://groups.google.com/d/msgid/neonixie-l/7e3257e3-e81f-4f76-b97e-9d564641af74n%40googlegroups.com.
