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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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12th Nov 2012, 2:44 pm | #1 |
Hexode
Join Date: Jul 2010
Location: Ireleth-in-Furness, Cumbria, UK.
Posts: 286
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Equivalent for a 6BA8 used in a Heathkit "Twoer"
I am repairing a Heathkit "Twoer" that has been long term loaned to our radio club.
I have found that the pentode section of the 6BA8 used as the output stage is dead. Any ideas what I could replace this with? I have a ECF80 that is in fairly good shape, but apart from being a totaly different pin out the data info is quite different. Or any ideas where I could obtain a 6BA8, I've already looked on well known auction site. Thanks Nick G0HIK |
12th Nov 2012, 3:06 pm | #2 |
Heptode
Join Date: Jan 2003
Location: Tewkesbury, Gloucestershire, UK.
Posts: 690
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Re: Equivalent for a 6BA8 used in a Heathkit "Twoer"
Hi Nick,
When you say the pentode section is dead, do you mean that it's heater doesn't light up? Otherwise it's unlikely to be completely dead which may point to another faulty component (o/p transformer?). If you do need to replace it, your ECF80 is not really suitable as it's a signal amplifier rather than an output valve. There doesn't appear to be a direct equivalent (other than the 6BA8A) so, if you can't find the correct valve your best bet would be an ECL80, 82 or 86. You would have to rewire the valvebase or make up an adaptor, however.
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Keith Yates - G3XGW VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm |
12th Nov 2012, 3:13 pm | #3 |
Heptode
Join Date: Jan 2003
Location: Tewkesbury, Gloucestershire, UK.
Posts: 690
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Re: Equivalent for a 6BA8 used in a Heathkit "Twoer"
Hmm - I've just realised that the output in question is on 144MHz and not audio as I initially thought so my reply is rather wide of the mark........
There are some 6BA8A's on Eb*y.
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Keith Yates - G3XGW VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm Last edited by Keith; 12th Nov 2012 at 3:19 pm. Reason: Additional info |
12th Nov 2012, 5:48 pm | #5 |
Hexode
Join Date: Jul 2010
Location: Ireleth-in-Furness, Cumbria, UK.
Posts: 286
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Re: Equivalent for a 6BA8 used in a Heathkit "Twoer"
First of all I should have said the valves in the set are 6B8A's, I did a search and did not come up with any, but I see that there are now two on the auction site.
I tested both valves on my valve tester and one tested as per the spec. The other tests okay for the triode, but no emission at all from the pentode section. The wire leading to the aerial connection has come adrift, so I presume the PA has been running into an open circuit load and damaged the tube. Thanks chaps Nick P.S. thanks for the link to the valve database, I did not know about it, now bookmarked. |