Hey. I started this build as an alternative at a power voltage divider able to offer reasonable voltage to supply the screen grids into a 6x6550 project. The available input voltage is 480-490V around and my intention was to reduce it to 360V somehow, keepin' the screen dissipation within the limit. At this voltage the screens draw at max power of 160W a total curent of 75 mA so the regulator should be able to support this current and bit more. ( roughly 30W).
I started inspired by this tubecad article :
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Using 1K series resistor and 12 pcs of 30V / 5W zeners I was able to make it stable for 100 mA draw within 15V regulation, meant less than 5 percent, which I consider pretty acceptable for application.
Assuring thermal conditions was a challenge. I ended with an unusual build, who helped by fan cooler ventilation keep the diodes at almost environmental temp. Measuring 30*C around on the diodes leads in a pretty proximity of diode case. It works very well for 2 days powered on my bench but I.m not sure I use it. It dissipate 40w. The unit is bulky and need to be fully ventilated, supposed will be mounted outside on the back of chassis. It have 70x70x210 mm.
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A compulsory safety cage was considered...kind of...
I started inspired by this tubecad article :
Using 1K series resistor and 12 pcs of 30V / 5W zeners I was able to make it stable for 100 mA draw within 15V regulation, meant less than 5 percent, which I consider pretty acceptable for application.
Assuring thermal conditions was a challenge. I ended with an unusual build, who helped by fan cooler ventilation keep the diodes at almost environmental temp. Measuring 30*C around on the diodes leads in a pretty proximity of diode case. It works very well for 2 days powered on my bench but I.m not sure I use it. It dissipate 40w. The unit is bulky and need to be fully ventilated, supposed will be mounted outside on the back of chassis. It have 70x70x210 mm.
A compulsory safety cage was considered...kind of...
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