Valve Identification & Use - UK Vintage Radio Repair and Restoration Discussion Forum

PJC58-Hythe · 3rd Aug 2022, 9:26 am

Over the past few days I have been testing and cataloguing the many valves I have. While doing this I came across a valve I can find no data for, it says 'Telephones and Cables Limited' on the label and AX294 is painted on the glass inside the envelope and also written on the label. I am assuming this might have been used in a voice repeater circuit? As you can see it is a triode with a single filament heater running vertically. Does anyone have data on this and / or know what it was used for?

I also have two other valves both EG100 one marked 230-250 and the other 220-230 with different bases. The radio museum site has data on this valve https://www.radiomuseum.org/tubes/tube_eg100.html but I was wondering what they were used in?

Hope someone can help, thanks

llama · 3rd Aug 2022, 10:37 am

It would appear the word "Standard" is missing from your label - the part remaining uses the familiar STC font as seen on SenTerCel rectifiers etc. Can't improve on your guess for its application though.
Graham

G6Tanuki · 3rd Aug 2022, 11:48 am

Yes it is a STC valve... They have a long history of valve manufacture, involving the Birmngham Small Arms company (BSA) and a brand name 'micromesh' - they ultimately became Brimar.

What your valve was originally intended for I don't know but some embedded part of the telephone network would be a fair suggestion.

Heatercathodeshort · 3rd Aug 2022, 12:20 pm

The EG100 you mention sound like some form of barretter. STC manufactured a large range of line amplifier valves for telephone applications. John.

ms660 · 3rd Aug 2022, 12:37 pm

Quote:

Originally Posted by PJC58-Hythe

I also have two other valves both EG100 one marked 230-250 and the other 220-230 with different bases.

The figures could be the rectifiers heater voltage, the EG100 was rated at 120mA according to this (book page 267):

https://nvhrbiblio.nl/biblio/boek/Th...01926-1946.pdf

Lawrence.

PJC58-Hythe · 4th Aug 2022, 6:23 am

G6Tanuki, The other side of the AX294 has a label on which is written the valve number and this covers the 'Standard' on the wrap around label.

Lawrence, Thanks for the link to the PDF they are definitely rectifiers according to the Radiomuseum website and the figures are for the heater voltages.

I'm still interested to know what equipment the AX294 and EG100 valves were used in, but I'm guessing it may well remain a mystery!

3rd Aug 2022, 9:26 am	#1
PJC58-Hythe Heptode Join Date: Sep 2010 Location: Hythe, Hampshire, UK. Posts: 630	Valve Identification & Use Over the past few days I have been testing and cataloguing the many valves I have. While doing this I came across a valve I can find no data for, it says 'Telephones and Cables Limited' on the label and AX294 is painted on the glass inside the envelope and also written on the label. I am assuming this might have been used in a voice repeater circuit? As you can see it is a triode with a single filament heater running vertically. Does anyone have data on this and / or know what it was used for? I also have two other valves both EG100 one marked 230-250 and the other 220-230 with different bases. The radio museum site has data on this valve https://www.radiomuseum.org/tubes/tube_eg100.html but I was wondering what they were used in? Hope someone can help, thanks Attached Thumbnails __________________ Peter - M0HYT - BVWS Member - GQRP Club http://www.retroworkshop.co.uk

3rd Aug 2022, 10:37 am	#2
llama Octode Join Date: Jun 2006 Location: St Osyth, Nr Clacton, Essex, UK. Posts: 1,482	Re: Valve Identification & Use It would appear the word "Standard" is missing from your label - the part remaining uses the familiar STC font as seen on SenTerCel rectifiers etc. Can't improve on your guess for its application though. Graham __________________ Half my stuff is junk - trouble is, I don't know which half!

3rd Aug 2022, 11:48 am	#3
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Valve Identification & Use Yes it is a STC valve... They have a long history of valve manufacture, involving the Birmngham Small Arms company (BSA) and a brand name 'micromesh' - they ultimately became Brimar. What your valve was originally intended for I don't know but some embedded part of the telephone network would be a fair suggestion. __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.

3rd Aug 2022, 12:20 pm	#4
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Valve Identification & Use The EG100 you mention sound like some form of barretter. STC manufactured a large range of line amplifier valves for telephone applications. John.

4th Aug 2022, 6:23 am	#6
PJC58-Hythe Heptode Join Date: Sep 2010 Location: Hythe, Hampshire, UK. Posts: 630	Re: Valve Identification & Use G6Tanuki, The other side of the AX294 has a label on which is written the valve number and this covers the 'Standard' on the wrap around label. Lawrence, Thanks for the link to the PDF they are definitely rectifiers according to the Radiomuseum website and the figures are for the heater voltages. I'm still interested to know what equipment the AX294 and EG100 valves were used in, but I'm guessing it may well remain a mystery! __________________ Peter - M0HYT - BVWS Member - GQRP Club http://www.retroworkshop.co.uk