neazoi
Advanced Member level 6
Hi there,
Here is a little audio amplifier I would like to try, since I have the tube and the headphones.
However, I would like to provide the filament voltage from the +12v one, so that a single 12v PSU can be used, without the need for the battery. I do not want to use semiconductors. The filament draws 240mA at 1.2V.
Can a simple voltage divider do the trick?
I worry about the isolation of the cathode and the anode, since this is direct heated, but also about the resistance of the filament prior to heating, which would lead to some unpredictable initial voltage on the filament?
Here is a little audio amplifier I would like to try, since I have the tube and the headphones.
However, I would like to provide the filament voltage from the +12v one, so that a single 12v PSU can be used, without the need for the battery. I do not want to use semiconductors. The filament draws 240mA at 1.2V.
Can a simple voltage divider do the trick?
I worry about the isolation of the cathode and the anode, since this is direct heated, but also about the resistance of the filament prior to heating, which would lead to some unpredictable initial voltage on the filament?