375 Joules PS for my monoblock tube amps

[Tubelab_com]

I didn't know resistors had voltage ratings too.......Yes, they do.

There is usually a blanket voltage rating spec for a resistor. In reality there are two important areas of concern. As stated there is the end to end voltage rating. Ignoring that one was the reason for the exploding resistor and cap I mentioned before. The cap shorted due to over voltage. This put the entire power supply across the 1 watt resistor which should have just fried to an open, but the sequence of failure events that Goat Guy outlined happened. When the lightning bolt from my power supply had "jumped the shark" with plenty of energy left, it ate that electrolytic and what was left of the resistor with an explosive BANG.

The other issue is end or body to surrounding stuff. This isn't often specified and is easily degraded by a scratch or chip in the costing. This IS a BIG DEAL on PCB designs, especially if there is a ground layer under the resistor. I was using output plate to driver plate feedback in the test amp and running the tube at 650 volts. The plate voltage at 160 watts output was probably in the 1200 volts peak range. This caused another lightning bolt from plate to what was the ground plating on the board.

four solar panels in series at only 140V DC.

I had an old Sorensen power supply that was rated for about 100 volts and maybe 8 to 10 amps. I had turned the internal pots to get about 120 volts out of it. I found an old 240 to 120 volt autotransformer that weighed about 40 pounds. I wired it in series with the power supply for a ballast. It had enough DCR to drop the voltage to somewhere in the 40 volt range shorted, but made a steel melting fireball of enormous proportions once the arc was struck and the test subjects moved apart. 6 to 10 inch arcs were common depending on the outside air. Cool, calm, damp air made for the most fun. All this happened long before digital video was possible.....the mid 70's.

 

[GoatGuy]

Hello GoatGuy,

What program are you using for the PS simulations? I would like to perform precise simulations; a 5.56 NATO approach rather than my punt gun method. Transformer has ⁷⁰⁰VCT 145mA plate winding.

Thank you.

I wrote it, HiFiAmps, from scratch.
PERL code.
Runs the sim in about 5 seconds on my relatively ancient Mac.

GoatGuy ✓

PS: the program creates a CSV file, which auto-opens in Excel. From there I just select EDIT-INSERT-CHART and then XY-Chart. In a few seconds up comes a smallish chart. Just use the mouse to resize it. Then ... SHIFT-ALT-4 to sub-screen capture to a JPEG file on the desktop. From there, upload it to a comment, like the fragment of this very screen!

 

[kodabmx]

High energy storage PSUs should have interlocks to prevent accidental contact. Alternatively, use real engineering to eliminate them where they are not needed.

I prefer natural selection. A High Voltage warning sticker is more than enough IMHO. (Yes, I'm joking. At least on a square)