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ilimzn 3rd April 2006 06:32 PM

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?

Tweeker 3rd April 2006 06:56 PM

20V Russian tubes such as GM70, GK71. Not all that common though.

Giaime 3rd April 2006 07:31 PM

Also 10V BIG ones. Think transmitting triodes...

SoNic_real_one 4th January 2010 03:34 AM

Look at the first letter encoding:
Tube numbering

kevinkr 4th January 2010 04:32 AM

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..

tomchr 4th January 2010 05:53 AM

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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