Need help identifying valve - UK Vintage Radio Repair and Restoration Discussion Forum

retailer · 23rd May 2007, 1:49 pm

I recently scored a box of 150 or so old valves. Most are telephony valves with some real oldies (tennis ball shape) as well as balloon shape and ST shape. I have been able through the internet to idenify all but 3 and am hoping someone can shed some light. The valves in question ( all the same ) are Cossor. They are pentodes with Cossor logo is printed on top, in the lower part of the logo is printed V9, base is BR7, shape is ST type very similar to an AC2/Pen. Filament measures 30 ohms when cold and didn't start to glow until at least 30 volts was applied to it. Apart from a handful of 6.3v GT series Octal valves in the box all the filaments are either 2.5v or 4v. On the side is a barely legible logo of some sort with 869 ( I think) printed in the lower half. Also on the side is printed VT103B which is I believe the GPO designation. I did a net search for VT103 and came up with 6SQ7 which this definately is not. I plugged one into my Taylor tester and using AC2/Pen settings with a 30volt filament the gM read about 7.5-8. I'll probably keep some of the power triodes as I've always wanted to build a stereo SE triode amp but have been unable to justify the cost of even new manufacture triodes just for tinkering.

paulsherwin · 23rd May 2007, 2:26 pm

You might find this site useful: http://www.valve-museum.org/

Paul

Jeremy M0RVB · 23rd May 2007, 3:25 pm

The CV Register shows VT103B to be a CV1672 - and the EVS sheet for that shows it to be based on a PEN36C.

It is a GPO number.

retailer · 24th May 2007, 12:45 pm

Thanks for the info guys, PEN36C that's it! I almost tossed them in the no good box as the 30ohm filament didn't register the continuity beeper on my digital meter, I just happened to leave the meter probes a bit longer than normal and noticed the reading dropping and settle on 30ohms.

23rd May 2007, 1:49 pm	#1
retailer Heptode Join Date: May 2005 Location: Adelaide, South Australia Posts: 541	Need help identifying valve I recently scored a box of 150 or so old valves. Most are telephony valves with some real oldies (tennis ball shape) as well as balloon shape and ST shape. I have been able through the internet to idenify all but 3 and am hoping someone can shed some light. The valves in question ( all the same ) are Cossor. They are pentodes with Cossor logo is printed on top, in the lower part of the logo is printed V9, base is BR7, shape is ST type very similar to an AC2/Pen. Filament measures 30 ohms when cold and didn't start to glow until at least 30 volts was applied to it. Apart from a handful of 6.3v GT series Octal valves in the box all the filaments are either 2.5v or 4v. On the side is a barely legible logo of some sort with 869 ( I think) printed in the lower half. Also on the side is printed VT103B which is I believe the GPO designation. I did a net search for VT103 and came up with 6SQ7 which this definately is not. I plugged one into my Taylor tester and using AC2/Pen settings with a 30volt filament the gM read about 7.5-8. I'll probably keep some of the power triodes as I've always wanted to build a stereo SE triode amp but have been unable to justify the cost of even new manufacture triodes just for tinkering.

23rd May 2007, 2:26 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Need help identifying valve You might find this site useful: http://www.valve-museum.org/ Paul

23rd May 2007, 3:25 pm	#3
Jeremy M0RVB Hexode Join Date: Jul 2003 Location: Leeds, West Yorkshire, UK. Posts: 458	Re: Need help identifying valve The CV Register shows VT103B to be a CV1672 - and the EVS sheet for that shows it to be based on a PEN36C. It is a GPO number.

24th May 2007, 12:45 pm	#4
retailer Heptode Join Date: May 2005 Location: Adelaide, South Australia Posts: 541	Re: Need help identifying valve Thanks for the info guys, PEN36C that's it! I almost tossed them in the no good box as the 30ohm filament didn't register the continuity beeper on my digital meter, I just happened to leave the meter probes a bit longer than normal and noticed the reading dropping and settle on 30ohms.