Martin: I'd never heard of pandicon tubes before! That's so cool! Driving
them seems like a real pain, though, what with all the mandatory
multiplexing going on. Probably less of a pain if you're willing to use a
microcontroller? I would love to see some of your work, if you have a
link.
One of Dance's chapters is about beam switching/trochotron counting
circuits, so I'm already stealing wholesale from that to build a clock.
Eric: when I was investigating options for my tuning fork timebase, I came
across a plethora of vacuum tube quartz crystals in the low-hundreds to
tens of kilohertz range. Of course, they're pretty old and probably have
poor temperature compensation, but it would solve your frequency problem
without "cheating". I've also seen some people using astable
multivibrators as frequency dividers, but by all accounts they're fiddly
beasts.
--Duncan
On Sun, 21 Aug 2022, Tidak Ada wrote:
Hi Duncan,
I have some Elesta EZ10 A/B tubes (1MHz resp. 500kHz) that could do the
job if I can get the MHz of the 4MHz TCXO at 400kHz in a 'fair' way.
There must be a way using heterodyne mixing, but that goes beyond my
technical knowledge. HP used the technology in some counters in their
early years.
The trouble is that the EZ10A is a hydrogen filled tube. Hydrogen
diffuses through glass, so there is a good chance that the tube is dead.
Another less fair way is to use (High levl)TTL or CMOS chips there.
After all, the TCXO is also a semiconductor oscillator.
The lower frequencies have to be divided by some Sylvania 6879 dekatrons.
The display part should exist by a GS12C, GS12D and GC12/4B and some
10-counters from the Ericsson house.
I am at the level to set up a test circuit for the Elesta's, but time and age
are the bottlenecks.
Anyhow, I like to save some of the Elesta's for my tube collection.
Another guy who may be able to help you is Graham McGuire, also a Neonixie-L
member
Cheers,
eric
-----Oorspronkelijk bericht----- Van: [email protected]
[mailto:[email protected]] Namens Duncan Townsend
Verzonden: zondag 21 augustus 2022 17:17
Aan: [email protected]
Onderwerp: RE: [neonixie-l] Self-introduction & tube trading
Thanks for the warm welcome!
Michail: part of the challenge for the 1j24b CPU is to build the whole thing
without any silicon. Building the muxing and decoding circuitry for the 5971s
without using a PIC is part of the fun! Of course, sourcing high-voltage
germanium diodes is a slog.
eric: I had read Joe's research radiomuseum.org but did not know that we shared
an _alma mater_. Thanks for the connection and the pointer to
tubecollectorsassociation! Re: quartz oscillators, how did you get the
frequency down into the dekatron range? IIRC, most dekatrons don't work until
you're down in the tens of kilohertz.
--Duncan
P.S. correction to my original email: I have a large quantity of ILC1 1/7 VFDs
not ICL1 1/7.
On Sun, 21 Aug 2022, Tidak Ada wrote:
Hello Duncan,
Interesting projects.
About those Russian rod-gridded tubes I will refer you to TCA-member [
[email protected] ] Joe Sousa (MIT). He did a lot of
research on these tubes. His reports are also published at
Radiomuseum.org [
https://duckduckgo.com/?q=radiomuseum.org+english+language&hps=1&atb=v
261-1&ia=web
]
I had plans for a clock with moving coil meter readouts, but I stopped after
calculating the power consumption of the project.
Intention was to start with a TC X-tal oscillator (400kHz) then count down with
dekatrons to the 0,1Hz region. Then a clock counter with a D/A converter to the
meters.
Unfortunately, the power consumption is irresponsible, especially in this time
of scarcity and hi prices in Europe.
Success!
eric (Tidak Ada)
-----Oorspronkelijk bericht-----
Van: [email protected] [mailto:[email protected]]
Namens Duncan Townsend
Verzonden: zondag 21 augustus 2022 3:53
Aan: n, the [email protected]
Onderwerp: [neonixie-l] Self-introduction & tube trading
Hello everybody!
I'm Duncan, an American software engineer by day and vacuum tube enthusiast
when I'm not distracted by other things. I have an unreasonable number of
pokers in the fire right now, but they include:
* a clock based on each of J.B. Dance's Electronic Counting Circuits
chapters (how low can I get the active part count without involving
silicon components?)
* tuning fork timebase for the above clocks
* 1j24b (Russian subminiature rod pentode) CPU
* 1j25r (even smaller than 1j24b) headphone amplifier
In particular, I'm interested in hearing from the experts what kind of fun
tube-based displays I might've overlooked for the 1j24b CPU. My current plan is
5971 13-segment tubes (I'm too poor for that many 7971s), but I don't really
know what's out there.
===
I'm also interested in trading to get some of the tubes I admire for
their aesthetics. I consider the National NL-90X series (NL-900 no
decimal,
NL-901 left decimal, NL-902 right decimal, NL-908 both decimals) as
well as the Ericsson GR10N tubes some of the most beautiful ever
manufactured and would love to trade for/buy some. I have a large
number of enormous
ICL1-1/7 VFDs as well as some tiny National NL-4998 nixies for trade.
I also have the above mentioned sub-subminiature Russian tubes (1c38a
triode, 1c38a-q Chinese variant triode, 1j25r pentodes, and tg5r
thyratron) as well as their slightly less sub- brethren (1c1a triode, 06p1a
pentode, 1t1a thyratron) for anyone who wants to build out their collection of
oddities.
--Duncan
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