850V difference is too much, you must use 4-5 piece 5-10W resistors (connected is series).
I don't recommend this solution, separate power supply is safer.
I don't recommend this solution, separate power supply is safer.
It is not really elegant, but hey, your choice. Burning 850V with some resistors doesn't add too much additional heat to such a large transmitting-tube-amp.
But when there is no current draw, the voltage will rise to the full 1000VDC. So each capacitor, tube socket, etc. must be able to withstand the 1000V...heck...even the driver tube. Just imagine when there is a heater fault and the tube ceases its emission. Anode voltage will rise to 1000V whereas cathode voltage will be at ground level.
Better solution is a resistor a some well designed shunt regulator or even an OA3/STV150 tube.
But when there is no current draw, the voltage will rise to the full 1000VDC. So each capacitor, tube socket, etc. must be able to withstand the 1000V...heck...even the driver tube. Just imagine when there is a heater fault and the tube ceases its emission. Anode voltage will rise to 1000V whereas cathode voltage will be at ground level.
Better solution is a resistor a some well designed shunt regulator or even an OA3/STV150 tube.
If there's no aversion to semiconductors a 150V Zener will do. Just make sure it'll handle the power.
If you have a center tap check my schematic here.
GM-70 All done. Is the thread name in this form. You can get 500v from a center tap if you have A bridge rectifier.
GM-70 All done. Is the thread name in this form. You can get 500v from a center tap if you have A bridge rectifier.
Instead of a high wattage resistor wasting lots of energy as heat, why not use a capacitor from the AC (transformer secondary side) with bridge rectifier and Zener? Work out the total current required and, from there, calculate the reactance at 60 Hz you need and then the capacitor value.
Of course, you will have to be mindful of the capacitor voltage rating and series two or more if necessary. This technique is often used in mains powered LED lights.
Of course, you will have to be mindful of the capacitor voltage rating and series two or more if necessary. This technique is often used in mains powered LED lights.
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With that much voltage... You might spend as much on power resistors to drop the voltage down to 150V as you would for another small transformer and the associated parts.
A separate supply would be my choice for anything more than a ma or two.
If you've got a filament winding, you could always use a cheap 120 to 6 transformer in reverse...
A separate supply would be my choice for anything more than a ma or two.
If you've got a filament winding, you could always use a cheap 120 to 6 transformer in reverse...
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