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Old 3rd April 2006, 06:32 PM   #1
ilimzn is offline ilimzn  Croatia
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Default Standard tube filament voltages and currents

I'm building a sort of universal tube filament power supply. It will have a constant current and a constant voltage mode, for series and parallel filament supply, value selecvtable by a multipole rotary switch.
Now, I have already selected the constant current ranges, for most of the standard series strings:
100, 150, 300, 450 and 600mA.
The standard voltages present more of a problem. What would be the more common standard filament voltages, apart from the usual suspects, these being 1.4V/1.5V, 2.8/3V, 5V, 6.3V and 12V?
I have looked at various tube tester manuals for this, but the higher voltage ranges are usually geared towards tubes intendedfor series filament connections, which I have already covered with constant current mode operation.
Anyone care to post some additions to either the current or voltage list?
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Old 3rd April 2006, 06:56 PM   #2
Tweeker is offline Tweeker  United States
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20V Russian tubes such as GM70, GK71. Not all that common though.
Be sure your foil hat has a good low impedance ground.
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Old 3rd April 2006, 07:31 PM   #3
Giaime is offline Giaime  Italy
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Also 10V BIG ones. Think transmitting triodes...
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Old 4th January 2010, 03:34 AM   #4
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Look at the first letter encoding:
Tube numbering
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Old 4th January 2010, 04:32 AM   #5
kevinkr is offline kevinkr  United States
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7.5V for certain vintage American DHTs like the 50, and the 10(Y).

4.0V for some vintage British DHTs like the PX4 and PX25.

3.8V for vintage German DHTs like the Aa, Ba, Bas, etc..
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
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Old 4th January 2010, 05:53 AM   #6
tomchr is online now tomchr  Canada
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One suggestion: Redefine the project to be a lab power supply with adjustable output voltage. Have a mode on this power supply that turns it into a current source with a variable output current. Something like 0~30 V, 0~5 A should cover quite a bit of ground, I'd think. Add a couple panel meters showing voltage and current and you'd have yourself quite a lab supply.

I seem to recall seeing tubes with 25.2 V filaments...

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