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Old 27th Jul 2020, 6:50 pm   #1
Norman Raeburn
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Default Calling the valve experts again!

Hi folks, Can anyone help me to identify this valve before it gets binned as useless. Itís a five pin one with top cap, I donít 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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Old 27th Jul 2020, 6:53 pm   #2
valves4amps
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Default Re: Calling the valve experts again!

Looks like an 807 to me.

Dave
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Old 27th Jul 2020, 7:38 pm   #3
Norman Raeburn
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Default 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.
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Old 27th Jul 2020, 7:56 pm   #4
turretslug
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Default 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
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Old 27th Jul 2020, 8:00 pm   #5
Jon_G4MDC
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Default Re: Calling the valve experts again!

Is it big enough for an 807?
Looks 6D6 or such like from here.
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Old 27th Jul 2020, 8:52 pm   #6
Norman Raeburn
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Default Re: Calling the valve experts again!

I will measure it up tomorrow although i think itís big enough to be an 807. Norman
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Old 27th Jul 2020, 10:12 pm   #7
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Default 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.
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Old 27th Jul 2020, 10:52 pm   #8
high_vacuum_house
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Smile Re: Calling the valve experts again!

Quote:
Originally Posted by ms660 View Post
Looks like an 807 to me too.

On the base:

"licensed only to extent indicated on carton"

No idea of the make.

Lawrence.
Good evening,

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
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Old 28th Jul 2020, 1:54 pm   #9
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Default 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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Old 28th Jul 2020, 4:19 pm   #10
Alan_G3XAQ
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Default 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
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Old 28th Jul 2020, 4:28 pm   #11
Norman Raeburn
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Default Re: Calling the valve experts again!

Thanks to all who responded, it is indeed an 807. It doesnít 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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