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    Building, troubleshooting and testing of these amplifiers should only be
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D3a pentode as driver? History of this tube?

I did not turn it. People turned, who started asking if I can organize a group buy. As the result, I have 3 offers: the first one turned to have limited stock and high prices; the second one, a lady wants to buy some American clothes; and the third one, a man offers good price, but I have to figure out how to pay.

Barretter; do you have a supply of D3A so we can buy them instead of 6J52P to play with?

However, history is an interesting thing, but we are about DIY here.
 
Yes you did. You invaded Poland. (This is a Monty Python reference). I suggest you look at your first post again.
This may be a DIY place but the man who started the thread specifically asked about the history of the D3a. I suggest that you look at the title of the thread again.
I have about 16 D3a, 30-odd E810Fs, 20 or so E280Fs and some E282Fs. Western European high gm pentodes ae not that hard to obtain. I am not a businessman.
 
Sorry. I'm not a businessman. I'm not selling tubes. I'm an engineer, and I don't have about 16 of D3a, but I would be satisfied by several 6J52P to play with and design some very simple, but very nice hybrid amp. I will start my own thread about it as soon as finish my current hybrid amp project.
 
Are you feeling better now? I didn't realise you were ill.

Did anybody actually get any 6J52s? My experience with the ones I bought on eBay were pretty negative : most of them didn't draw enough current to light an LED and the very few that did work were microphonic (possibly this could have been cured with the right grid stoppers) but they were probably all pulls. Is there any new old stock of them?
 
There are a fair amount of 6J52P on eBay right now, I bought four some months ago.. Have not quite figured them out, have a uTracer and am getting surprisingly inconsistent results in some respects - might be doing something wrong.

Just bought 4 more NOS 6J52P made by Souz in the 1980s, will see how they compare.
 
No, I am neither better nor ill. Just being sarcastic about jokes about invading Poland by Germans, Russian, Turks etc. Sorry if it is not funny to you about 300 men from a tribe from current teritory of Poland crossing the Channel trying to invade Britain 1000 yrs ago. That is history.

Beg your pardon for an OT.
 
The joke in Fawlty Towers was not about Poland, it was about the obsession of a certain kind of British person with the Germans and the Second World War. You probably have to be British to appreciate how funny the line is.
Lots of people were invading these islands in the period you mention and I have no reason to doubt your history. I was just rather surprised that such a long dormant thread had been re-opened with such a comment.
 
Hi,
i´m a great fan of Monty Python and Fawlty towers and John Cleese and Terry Gilliam and ....
The D3a was a special tube designed from TFK for the German Post as a Broadband Amplifier maybe in the late 50s.
Here is a link to "Jogis Roehrenbude" where you can see some pics of it:
Deutsche Behoerdenroehren / Postroehren - D3a
Information is not so much about the tube history but there are great pics.
Also you have a link at the bottom of that page for the TFK Datasheet.
There are some more information at the blog of Thomas Mayer:http://vinylsavor.blogspot.de/search/label/D3a
Have fun,
Hilmar
 
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