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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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27th Jul 2020, 6:50 pm | #1 |
Heptode
Join Date: Feb 2008
Location: Leven, Fife, Scotland
Posts: 823
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Calling the valve experts again!
Hi folks, Can anyone help me to identify this valve before it gets binned as useless. It’s a five pin one with top cap, I don’t know how you count the pins on it but if you assume the single pin to be pin 1 then the heaters are on 3 and 4. I stuck some volts on 3&4 and with 4v applied the heater draws 700ma. I have searched for some clues and I cannot see any marks on the glass. Anyhow here are the pics. Thanks in anticipation. Norman
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27th Jul 2020, 6:53 pm | #2 |
Triode
Join Date: Sep 2006
Location: Broughton Preston Lancashire, UK.
Posts: 42
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Re: Calling the valve experts again!
Looks like an 807 to me.
Dave |
27th Jul 2020, 7:38 pm | #3 |
Heptode
Join Date: Feb 2008
Location: Leven, Fife, Scotland
Posts: 823
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Re: Calling the valve experts again!
Hi Dave, I had thought about an 807 but when i looked that up it says it’s metallised which made me doubt it. I have no idea but i will check and see if my valve tester can do one. Many thanks, Norman
Don’t know what i was looking at earlier but an 807 looks a distinct possibility. |
27th Jul 2020, 7:56 pm | #4 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,400
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Re: Calling the valve experts again!
807-alikes were made by lots of different valve-makers with their own particular production detailing, some more esteemed than others, and an image search throws up quite a few with very similar-looking electrode structures.
Colin |
27th Jul 2020, 8:00 pm | #5 |
Nonode
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 2,015
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Re: Calling the valve experts again!
Is it big enough for an 807?
Looks 6D6 or such like from here. |
27th Jul 2020, 8:52 pm | #6 |
Heptode
Join Date: Feb 2008
Location: Leven, Fife, Scotland
Posts: 823
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Re: Calling the valve experts again!
I will measure it up tomorrow although i think it’s big enough to be an 807. Norman
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27th Jul 2020, 10:12 pm | #7 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Calling the valve experts again!
Looks like an 807 to me too.
On the base: "licensed only to extent indicated on carton" No idea of the make. Lawrence. |
27th Jul 2020, 10:52 pm | #8 | |
Octode
Join Date: May 2003
Location: Belper Derbyshire
Posts: 1,936
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Re: Calling the valve experts again!
Quote:
I think that narrows it down a bit to a US manufacturer as I have seen this written on many US Bakelite based valves but not of UK manufactured valves. It may under bright light be possible to look down the pinch and see where the electrode wires go to which pins. This would help to identify the valve type. Can you see whether the top cap is connected to the anode or the control grid? Christopher Capener
__________________
Interests in the collection and restoration of Tefifon players and 405 line television |
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28th Jul 2020, 1:54 pm | #9 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,643
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Re: Calling the valve experts again!
It appears to have a screen around the exposed internal support structure if that's a clue?
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28th Jul 2020, 4:19 pm | #10 |
Pentode
Join Date: Apr 2018
Location: Canterbury, Kent, UK.
Posts: 189
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Re: Calling the valve experts again!
There are some good pics of an 807 here for comparison
http://www.r-type.org/exhib/aaq0161.htm Sometimes breathing on the glass makes the markings appear briefly. Best wishes, Alan G3XAQ |
28th Jul 2020, 4:28 pm | #11 |
Heptode
Join Date: Feb 2008
Location: Leven, Fife, Scotland
Posts: 823
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Re: Calling the valve experts again!
Thanks to all who responded, it is indeed an 807. It doesn’t test 100% but should be usable. The gm quoted in the Taylor manual is 4.1 and it tests at 3.4. I suspect that is perfectly acceptable but await to be educated. Many thanks again, Norman
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