Welcome! Need support, you got it. Or share you ideas and experiences.
In Reply to: Heater supply posted by jdhart on March 28, 2006 at 14:01:33:
It's best for tube life ot operate them at 6.3v or a little lower. Remember that the primary on the LL1683 is rated for 115v, so if your line voltage is like mine (122-124v), you can add another 5% to that 6.6v.
I prefer a series resistor, because it reduces the cold filament inrush current a bit. You need about a 0.15-0.2 ohm resistor rated at 2 watts or more to get to about 6.3v.
And if I want to separate the channels, and run just 2 6SN7 per secondary, then it appears I need to drop a resistor in parallel to the heaters to drop some of the excess current, correct?
If the two 6SN7s together need 1.2A of current and the winding provides up to 3A of current...that is either running the winding pretty hot, or I need to disapate some of the current.
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