Capacitor heating tube

How to connect heater filament to 220 volt AC?

simply tie one end of the filament to GND, and other end to the voltage-dropping capacitor. The cap handles most of the 220 volts. I wonder, whether I can instead connect heater filament directly to 220V AC via suitable capacitor to limit current.

Can a heater filament be used as a voltage divider?

Think about it for a moment. You are using the capacitor as a voltage divider, with the heater filament as the second part of the divider. If you add more tubes in series, you change the divider ratio. Also, heater filaments aren't simple resistors. Like light bulb filaments, their resistance is low when cold and higher when hot.

Why do I need a tube heater supply?

Using the Tube Heater Supply will provide a much lower noise floor as the heaters will now be fed with a nice clean DC supply. PLEASE NOTE: The input AC voltage should not be more than 1V above the desired DC voltage output.

How hot does a capacitor get on a warm PCB?

All other capacitors I've touched were always cool, even when used on a warm PCB. So I'm getting 45.5 °C on the cap of the capacitors. The outside temperature is 27.8 °C. The temperature of the PCB itself (measured from an exposed, unpopulated, solder pad) is 35.7 °C.

How long can a capacitor last at a rated temperature?

You can buy capacitors with 3000 hour or 5000 hour or even longer lifetimes at rated temperature, but cost is liable to be higher to much higher. You can buy capacitors with higher than 105C temperature ratings but they are usually much less common and probably expensive. There are many well known & reputable brands.

How do you heat a vacuum tube?

As I understand vacuum tubes (like triode / pentode) usually are designed to be heated with certain current through the filament. And usually it is about low-voltage and comparatively high-current. E.g. 6.3 V at 300mA. Schematics I usually find around use transformer to get this heating voltage.