|
General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
|
Thread Tools |
22nd Oct 2021, 9:33 am | #1 |
Heptode
Join Date: May 2014
Location: Salisbury, Wiltshire, UK.
Posts: 998
|
Valve colours
Question, Among these valves I have to sort and sell (apologies for huge delays, a house fire and subsequent repairs are slowing me right down) I have a few that are fully coated externally with red coating, some with green coating. They look truly beautiful but resumably they werent coated for that reason. Can someone say what it is and why it was done? Im assuming it's to keep something IN rather than out, but why the pretty colours?
D
__________________
David, G4YVM. |
22nd Oct 2021, 9:43 am | #2 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,427
|
Re: Valve colours
The red coating on some valves was conductive and used for screening, grey coating was also used. I have not seen green. Mullard used red, perhaps marketing has the EF50 valve had a metal cover that was painted red.
See EF39 for the conductive coating connection pin 1 http://www.r-type.org/exhib/aad0089.htm
__________________
Frank |
22nd Oct 2021, 9:56 am | #3 |
Moderator
Join Date: Dec 2010
Location: Exeter, Devon and Poole, Dorset UK.
Posts: 6,823
|
Re: Valve colours
I have seen Green coated valves on some war era battery portables the other colour you see a lot pre war was Gold particularly Mullard.
Red and grey are still the most common. Cheers Mike T
__________________
Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |
22nd Oct 2021, 1:00 pm | #4 |
Heptode
Join Date: May 2014
Location: Salisbury, Wiltshire, UK.
Posts: 998
|
Re: Valve colours
Ah yes, I have a gold one too...beautiful.
I have considered building a small display stand to show off these beauties.
__________________
David, G4YVM. |
22nd Oct 2021, 1:11 pm | #5 |
Octode
Join Date: Mar 2015
Location: Yorkshire, England.
Posts: 1,294
|
Re: Valve colours
Three (rather dusty) gold Mullard valves in a Philips 785 AX monoknob. They are rather pretty, aren't they?
__________________
Regards, Ken. BVWS member |
22nd Oct 2021, 2:05 pm | #6 |
Heptode
Join Date: May 2014
Location: Salisbury, Wiltshire, UK.
Posts: 998
|
Re: Valve colours
Very!
__________________
David, G4YVM. |
22nd Oct 2021, 2:36 pm | #7 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
|
Re: Valve colours
A very pale green was used on some WWII 'CV' valves as found in the likes of the WS18 and WS38 - they were Mazda Octal type but with a parallel sided envelope rather than the usual Mazda shouldered bottle.
__________________
I'm the Operator of my Pocket Calculator. -Kraftwerk. |
22nd Oct 2021, 5:40 pm | #8 |
Dekatron
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,549
|
Re: Valve colours
The gold ones are really bright when they are NOS.
|