07-29-2026, 01:49 PM
Hi MZip,
2V tubes for the early battery sets are directly heaters just like the 1.4V tubes in your set, not center tapped and were designed to be run off a 2V lead acid cell, 2.5V Eveready Air cell or 2 #6 dry cells in series with the required dropping resistor.
If you are designing a battery powered system to provide 90V for the B+, don't worry about powering an LM317 from a 6V battery for the tubes. Running the tube filaments from a 1.5V alkaline D cell is not harmful in any way
2V tubes for the early battery sets are directly heaters just like the 1.4V tubes in your set, not center tapped and were designed to be run off a 2V lead acid cell, 2.5V Eveready Air cell or 2 #6 dry cells in series with the required dropping resistor.
If you are designing a battery powered system to provide 90V for the B+, don't worry about powering an LM317 from a 6V battery for the tubes. Running the tube filaments from a 1.5V alkaline D cell is not harmful in any way
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis
Best Regards,
MrFixr55
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