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SisterOfMercy
Joined: 31 Oct 2007
Posts: 155
Location: Zwart Nazareth, The Netherlands
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| Posted: Sun Jun 23, 2013 12:16 am Post subject: Filament voltage |
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The service manual of my 1209s/E specifies 6.75V as the correct filament* voltage. The 909 uses a filament voltage of 6.3V, which drops to 6.0V after one minute. Should I / Can I turn down the filament voltage on my 1209s/E to 6.3V?
Does anybody have a datasheet on the P19 tubes? Maybe it is a better idea to use a current source, with a LM317 wired up the correct way..
*Filament, heater... I don't really get the difference yet..... find out for yourself, please.
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Sun Jun 23, 2013 12:21 am Post subject: |
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As I remember 6.3V seems correct,
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sun Jun 23, 2013 12:25 am Post subject: |
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Hello
The filament IS the heater. Electrons will not flow off of the cathode to form the beam unless the cathode is heated.
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SisterOfMercy
Joined: 31 Oct 2007
Posts: 155
Location: Zwart Nazareth, The Netherlands
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| Posted: Sun Jun 23, 2013 12:52 am Post subject: |
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| Tim in Phoenix wrote: | | The filament IS the heater.. |
Yes, but not the other way around. Or something like that. It has to do with direct and indirect heating of the tube. I forgot and am currently to drunk to think. (not that I can think when I'm sober).
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Sun Jun 23, 2013 1:05 am Post subject: |
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Nope the filament is the heater. Rum ? 
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Sun Jun 23, 2013 1:05 am Post subject: |
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Nope the filament is the heater. Rum ?
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SisterOfMercy
Joined: 31 Oct 2007
Posts: 155
Location: Zwart Nazareth, The Netherlands
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| Posted: Sun Jun 23, 2013 1:15 am Post subject: |
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Well... I don't know, and I don't care... wouldn't it be an upgrade to use a LM317 per tube (!) as a current source, like this:
http://i.stack.imgur.com/YvyY3.png
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