Calling the valve experts again! - UK Vintage Radio Repair and Restoration Discussion Forum

Norman Raeburn · 27th Jul 2020, 6:50 pm

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

valves4amps · 27th Jul 2020, 6:53 pm

Looks like an 807 to me.

Dave

Norman Raeburn · 27th Jul 2020, 7:38 pm

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.

turretslug · 27th Jul 2020, 7:56 pm

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

Jon_G4MDC · 27th Jul 2020, 8:00 pm

Is it big enough for an 807?
Looks 6D6 or such like from here.

Norman Raeburn · 27th Jul 2020, 8:52 pm

I will measure it up tomorrow although i think it’s big enough to be an 807. Norman

ms660 · 27th Jul 2020, 10:12 pm

Looks like an 807 to me too.

On the base:

"licensed only to extent indicated on carton"

No idea of the make.

Lawrence.

high_vacuum_house · 27th Jul 2020, 10:52 pm

Quote:

Originally Posted by ms660

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

AC/HL · 28th Jul 2020, 1:54 pm

It appears to have a screen around the exposed internal support structure if that's a clue?

Alan_G3XAQ · 28th Jul 2020, 4:19 pm

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

Norman Raeburn · 28th Jul 2020, 4:28 pm

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

27th Jul 2020, 6:50 pm	#1
Norman Raeburn Heptode Join Date: Feb 2008 Location: Leven, Fife, Scotland Posts: 823	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 Attached Thumbnails

27th Jul 2020, 6:53 pm	#2
valves4amps Triode Join Date: Sep 2006 Location: Broughton Preston Lancashire, UK. Posts: 42	Re: Calling the valve experts again! Looks like an 807 to me. Dave

27th Jul 2020, 7:38 pm	#3
Norman Raeburn Heptode Join Date: Feb 2008 Location: Leven, Fife, Scotland Posts: 823	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
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,400	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
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	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
Norman Raeburn Heptode Join Date: Feb 2008 Location: Leven, Fife, Scotland Posts: 823	Re: Calling the valve experts again! I will measure it up tomorrow although i think it’s big enough to be an 807. Norman

27th Jul 2020, 10:12 pm	#7
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	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.

28th Jul 2020, 1:54 pm	#9
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Calling the valve experts again! It appears to have a screen around the exposed internal support structure if that's a clue?

28th Jul 2020, 4:19 pm	#10
Alan_G3XAQ Pentode Join Date: Apr 2018 Location: Canterbury, Kent, UK. Posts: 189	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
Norman Raeburn Heptode Join Date: Feb 2008 Location: Leven, Fife, Scotland Posts: 823	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