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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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8th Jan 2017, 4:37 pm | #1 |
Pentode
Join Date: Dec 2012
Location: Cardiff, UK.
Posts: 211
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Valve identification
Hi, I have a number of what look like EL84 and ECC83 valves that I wish to use but have lost their markings. Is there a proven method of identification that one can use to help with this?
Thanks. |
8th Jan 2017, 4:48 pm | #2 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,338
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Re: Valve identification
Well the envelope is much longer on the EL84 and you can only see the one eletrode assembly. The ECC83 is quite stubby and you can clearly see the 2 triode assemblys side by side.
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Edward. |
8th Jan 2017, 4:49 pm | #3 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,642
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Re: Valve identification
Have a look here: http://www.r-type.org/
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8th Jan 2017, 4:55 pm | #4 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,578
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Re: Valve identification
EL 84's are quite easy to identify. ECC83's can be a little more difficult. At one time, the ECC83 had a shorter anode than an ECC82. I have however got several ECC83's that look identical to ECC82. Some members familiar with factory markings may have a sure-fire method of identification. Why not start off by posting some good close-up pictures?.
Of course your EL84's could be UL84's (or even PL84's). No way of telling those apart by looks.
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8th Jan 2017, 6:37 pm | #5 |
Octode
Join Date: Feb 2009
Location: Bletchley, Buckinghamshire, UK.
Posts: 1,223
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Re: Valve identification
Have they lost *all* their markings? If they were made by any of the Philips factories dotted around the world, there would have been a set of numbers near the valve base that can be decoded to give the valve type. They often remain after all other print has rubbed off.
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9th Jan 2017, 11:39 pm | #6 |
Hexode
Join Date: Oct 2007
Location: Ossett, West Yorkshire, UK.
Posts: 406
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Re: Valve identification
Hi,
Mullard code rX for EL84, I6 for ECC83. Google "Mullard Factory Valve Codes" for a full list. Shame nobody has done an Excel file for them. Or have they? David |
10th Jan 2017, 12:10 am | #7 |
Dekatron
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
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Re: Valve identification
I have a copy of the Philips code list in pdf format which has been reproduced in machine readable characters rather than a scan. Not sure where it came from.
There are various tricks for revealing worn away printing. Use a strong light source and look at the reflective light or breath on the valve to create a light mist. Last edited by PJL; 10th Jan 2017 at 12:15 am. |
10th Jan 2017, 1:51 am | #8 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,642
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Re: Valve identification
There are a couple of lists, and they can be a bit fiddly to translate. I find it easier to work out the probables, there'll only be a couple, and look the code up for confirmation.
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