Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Sep Mon 16, 2019 5:21 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 9 posts ] 
Author Message
 Post subject: Amperex Z502S tube
PostPosted: Aug Sat 17, 2019 4:58 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 4513
Location: Charleston, W.Va.
In a tube collection which I recently purchased, I found this one which is unlike anything I have ever seen before:

NOS in original yellow/green Amperex box: Amperex Z502S. The tube itself is branded for Amperex; it bears the tube number as well as "Made in Great Britain". From the style and fonts of the white ink-stamping I would say it was almost certainly manufactured by Mullard.

I have done some limited internet research on this tube. It is said to be a "cold cathode counting tube", 4k pps Bi-directional Selector Dekatron base. Frankly, I don't know what any of this means. All I know is that in terms of physical appearance, this tube is a thing of beauty to behold.

What exactly is the Z502S tube, and what was its application? Does it have any value in the current marketplace? Should I keep it or discard it?

_________________
Poston


Top
 Profile  
 
 Post subject: Re: Amperex Z502S tube
PostPosted: Aug Sat 17, 2019 5:50 am 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 37470
Location: Livermore, CA
Hi Poston

A counter tube used in test equipment. Instead of numbers this one has a dot that goes around. Somewhat like hands on a clock.

https://frank.pocnet.net/sheets/030/z/Z502S.pdf

_________________
Norm


Top
 Profile  
 
 Post subject: Re: Amperex Z502S tube
PostPosted: Aug Sat 17, 2019 8:02 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 4513
Location: Charleston, W.Va.
Norm Leal wrote:
Hi Poston

A counter tube used in test equipment. Instead of numbers this one has a dot that goes around. Somewhat like hands on a clock.

https://frank.pocnet.net/sheets/030/z/Z502S.pdf

Hi Norm,
Thanks for your response and the link to the Phillips datasheet.

Maybe something like a nixie tube, except you read it from the top rather than the side? So when the dot stops you read the numerical position?

Would this have been used, for example, in a frequency counter? Maybe several of them arrayed in a row, you read the position of the dots and translate that into a number?

This is very fascinating to me, since before this I never knew such tubes existed.
Here is an interesting website I found which has several good photos of this tube, and also an animation showing it spinning:
http://www.tube-tester.com/sites/nixie/ ... -valvo.htm


It seems odd that I would have found this tube in a big collection of ten tube caddies I purchased from the deceased owner of a long-closed local radio/TV repair shop. There must be 3,000 or more NOS boxed tubes in these ten caddies; almost all are TV tubes but a few for radio/audio. It seems strange that this Z502S would have been among them.

_________________
Poston


Top
 Profile  
 
 Post subject: Re: Amperex Z502S tube
PostPosted: Aug Sat 17, 2019 8:11 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 37470
Location: Livermore, CA
Hi Poston

Like a nixie tube but earlier. A group of them could be used on a counter to read frequency. Maybe the store owner had test equipment that used this tube?

_________________
Norm


Top
 Profile  
 
 Post subject: Re: Amperex Z502S tube
PostPosted: Aug Sat 17, 2019 9:57 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5008
Location: Perrysburg, OH, U.S.A.
Our glass plants used to use glass container wall thickness testers that used a Strontium 90 Beta source. By law they had to be check for leakage of the radioactive material at regular intervals. Swabs from the testers were checked with a detector connected to a scalar counter like this:
Attachment:
Scalar Counter.jpg
Scalar Counter.jpg [ 134.81 KiB | Viewed 211 times ]

John

_________________
“Never attribute to malice that which can be adequately explained by stupidity.”
― R. A. Heinlein


Top
 Profile  
 
 Post subject: Re: Amperex Z502S tube
PostPosted: Aug Sun 18, 2019 2:13 am 
Member
User avatar

Joined: Sep Mon 16, 2013 2:42 am
Posts: 3424
Location: Tucson, Arizona U.S.A.
No, it's not like a Nixie tube. A Nixie tube has the number electrodes in it and that's all. It requires an external counter. A Dekatron has the counter built in although it does require a multi-phase drive signal. The upper frequency limit of 4KHz (for yours, other types had other limits) pretty much eliminates it's use in frequency counters. They were mostly used in nuclear instrumentation. If you search the web you will find circuits for demonstrating it.

_________________
Jim Mueller


Top
 Profile  
 
 Post subject: Re: Amperex Z502S tube
PostPosted: Aug Sun 18, 2019 2:35 am 
Member
User avatar

Joined: Feb Sun 05, 2012 5:12 pm
Posts: 873
Location: North Syracuse NY 13212
Google "dekatron spinner" to see some of those tubes in action.

Bob

_________________
Life is too short to be serious all the time.


Top
 Profile  
 
 Post subject: Re: Amperex Z502S tube
PostPosted: Aug Sun 18, 2019 3:01 am 
Member
User avatar

Joined: Jul Sun 17, 2011 1:11 am
Posts: 4434
Location: Tehachapi, CA - Bottom end of the Sierras
I became fixated on dekatrons back ~2004. I've built a few projects using them:

https://threeneurons.wordpress.com/dekatron-stuff/
https://threeneurons.wordpress.com/deka ... on-clocks/

Your Z502S is equivalent to a British Ericsson (Yes, started by the same Ericsson cellphone maker, but split off just before WWII. Now part of Siemens) GS10C and the Sylvania 6476A. It has a duodecal+1 base, and uses an odd socket:

https://frank.pocnet.net/sheets/022/g/GS10C-S.pdf
https://frank.pocnet.net/sheets/168/6/6476A.pdf

You used phased pulses,to advance the glow. Its a decade counter, but it does it in a way that semiconductor integrated circuits DO NOT. But by the late 60's an IC could count 1000 times faster, and do it with only a 5V supply (as opposed to 450V), and at a fraction of the cost.

Still not as much fun as these tubes.

https://www.youtube.com/watch?v=15II0yrt3kI
https://www.youtube.com/watch?v=EqY_UscOtjQ

btw: Amperex was part of the Philips Family, which included: Mullard, Philips & Valvo.

_________________
Life is like a roll of toilet paper - The closer you get the end, the faster it goes - A.E. Neuman


Top
 Profile  
 
 Post subject: Re: Amperex Z502S tube
PostPosted: Aug Mon 19, 2019 1:44 am 
Member
User avatar

Joined: Sep Mon 16, 2013 2:42 am
Posts: 3424
Location: Tucson, Arizona U.S.A.
The tubes in the above links are filled with neon and light up orange. Other types are filled with argon and light violet.

_________________
Jim Mueller


Top
 Profile  
 
Post New Topic Post Reply  [ 9 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 7 guests



Search for:
Jump to:  




























Privacy Policy :: Powered by phpBB