Hello
what could be the reason for this, EL34 tube defective, OPT defective?
in a circuit diagram for the amplifier that I found
there is a 12V Zener diode parallel to the grid resistor
which is here not present !?
what could be the reason for this, EL34 tube defective, OPT defective?
in a circuit diagram for the amplifier that I found
there is a 12V Zener diode parallel to the grid resistor
which is here not present !?
Screen grid resistor overload happens frequently with tube burnout.
Most of the time a 1 Watt resistor is preferred.
Most of the time a 1 Watt resistor is preferred.
Tubes made long ago had much more robust screen grids. Amps that were designed for these tubes put too high a voltage on the screens, hastening failure of modern-production tubes. Replace those 270ohm1w with 1K5W. Zeners aren't doing enough voltage dropping, prob just remove them.