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EF80/EF183/EF184.

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malcscott
(@malcscott)
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Hi, can i use an EF183 or an EF184 in place of an EF80? Cheers, Malc.

 
Posted : 07/04/2012 12:05 pm
Anonymous
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Same connections on all 3, so it can't hurt to try :)
http://www.radiomuseum.org/tubes/tube_ef80.html
http://www.radiomuseum.org/tubes/tube_ef183.html
http://www.radiomuseum.org/tubes/tube_ef184.html

EF80 <-> EF184 listed as predecessor - successor
Which of course sometimes means little.

EF180 is listed a 4mA Screen current max and EF80 listed as 2.8mA Screen current max, so it's likely that EF184 sub for an EF80 will not hurt and might work, but the other direction might not be a good idea depending on circuit.

I don't know really, but if it was mine I'd try it.

 
Posted : 07/04/2012 12:17 pm
crustytv
(@crustytv)
Posts: 12254
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Do you not have any EF80's Malc? normally they breed overnight and you find loads of them in peoples collections. If you don't Sue is going over your way in about 30 mins she can drop one in for you.

I can test if you wish but they are made of stern stuff

Chris

CrustyTV Television Shop: Take a virtual tour
Crusty's TV/VCR Collection: View my collection

 
Posted : 07/04/2012 12:26 pm
malcscott
(@malcscott)
Posts: 1560
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Topic starter
 

Hi Chris, many thanks for the offer. I have many EF80,s but i was trying to find a use for a box full of nos EF183/4. Cheers, Malc :thumbl:

 
Posted : 07/04/2012 12:31 pm
crustytv
(@crustytv)
Posts: 12254
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Thought so

I've been checking regarding the use of ef183/4 all I could find so far is that and EF183 can be used instead of an EF89 so that would help Mike.

I have a suite of Mullard Technical manuals that go into valves in great details, more than the normal reference books I will have a look through those in a minute and see what they say. I would tend to think what Mike said is true backwards yes forwards no so an EF183 should work not other way though.

Chris

CrustyTV Television Shop: Take a virtual tour
Crusty's TV/VCR Collection: View my collection

 
Posted : 07/04/2012 12:35 pm
Anonymous
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You mean EF184, Chris?
I think EF183 isn't exactly "later" EF89.

The EF80 and EF89 are pretty common though.

The EF85 and EF89 are slightly different pins
EF85 k = 1 & 3, shield = 6
EF89 k = 3, shield = 1 & 6
EF183 is same pins as EF85 and listed as a successor.
EF80, EF85, EF183, EF184 are all identical pins. The EF89 is curiously inferior having only one Cathode connection.

So I think
EF80 -> EF184
EF85 -> EF183
EF89 -> ?? (Perhaps an EF183 depending on circuit, if Cathode on EF89 is at chassis/OV)

The pin + internal wire to cathode tube has inductance and resistance. This then if you have a single cathode pin is in series with Grid-Cathode and Anode-Cathode voltages creating feedback.
The idea of two cathode connection is that one is dedicated to the grid circuitry and one to the Anode circuitry. It can give better RF performance, so it's strange the EF89 has a 2nd screen/shield pin instead. Obviously if an EF89 has any cathode circuitry (say common grid or decoupled bias resistor) then the EF184 or EF183 would short 1 & 3 and "earth" the cathode.

 
Posted : 07/04/2012 12:47 pm
Terrykc
(@terrykc)
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IIRC the EF18x series are known as frame grid types.

I think Philips replaced the normal grid supports with a more substantial frame structure which improved/stabilised the grid geometry.

They used this to reduce inter-electrode spacing in the valve resulting in a higher gain.

See if your detailed data agrees with that, Chris!

As for use as an EF8x substitute, different inter-electrode capacities might cause problems, as well as the higher gain.

It might be interesting to try them out in known working sets to see what differences are found.

When all else fails, read the instructions

 
Posted : 07/04/2012 12:48 pm
Anonymous
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I agree Terry,

Also higher gain in an IF stage can result in strange AGC instability or IF feedback

 
Posted : 07/04/2012 1:03 pm
Terrykc
(@terrykc)
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Hence my suggestion to try them out in known working sets ...

I would suggest more than one test, though!

On the basis that nobody is ever likely not to be within range of a serviceable supply of EF80s, I would suggest hanging onto stocks of NOS EF18x valves so that they are still around when a genuine need arises!

When all else fails, read the instructions

 
Posted : 07/04/2012 1:13 pm
Anonymous
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Yes, it's my impression that eBay is groaning under the weight of NOS / NIB EF80 and EF89 and the EF183 / EF184 are much rarer ass both only released in 1960 when Valve gear in serious decline (TVs using them longer than Radio generally I suppose, so I'd guess very few radio compared with TVs using EF18x. My 1962 German radio is EF89. EF89 seems to have been common from late 1950s to the end of Valve Radios)

 
Posted : 07/04/2012 1:40 pm
Terrykc
(@terrykc)
Posts: 3996
Member Rest in Peace
 

I only recall EF18x in TVs, probably as the features were particularly attractive for high gain/bandwidth designs, such as TV IF strips.

Some were prone to inter-electrode shorts, with associated burn-ups, due to the reduced internal clearances, no doubt.

Certainly worth hanging on to if you have them.

I think the EF80 will last for ever ...

When all else fails, read the instructions

 
Posted : 07/04/2012 1:50 pm
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