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I need to build a power supply that takes 127v AC and outputs 3 DC voltages: +90V, +1.4V, -4.5V. It is for a small tube amp, actually I'm powering the amp with batteries. I general terms, can you please tell me what components I will need and how to build it? Thanks.

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    \$\begingroup\$ Why do you need to build it yourself? Can't you use standard AC/DC supplies (not wall-warts, but these metal screw-terminal supplies like this one?) \$\endgroup\$
    – anrieff
    Mar 25, 2023 at 23:38
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    \$\begingroup\$ Add to your question the current of each voltages you want to generate. Do you need 10A or only 0.1mA ? This decides which components or circuits are useful in this case. \$\endgroup\$
    – MikroPower
    Mar 26, 2023 at 1:03
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    \$\begingroup\$ Include more details. Tell us the necessary current for each voltages. \$\endgroup\$
    – MikroPower
    Mar 26, 2023 at 1:07
  • \$\begingroup\$ Thanks, about 50mA for 1.4v and 10mA for the others. \$\endgroup\$ Mar 26, 2023 at 1:56
  • \$\begingroup\$ What about the tube filaments? Also, you mention powering the amp with both an AC source and batteries. Which is it? \$\endgroup\$
    – AnalogKid
    Mar 26, 2023 at 3:46

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Well, I just found the exact answer I needed here: https://antiqueradio.org/art/PowerSupplySchematic.jpg

The amp is very similar to those antique tube radios, so this schematic should do what I need. Thanks all.

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    \$\begingroup\$ This really isn't that good a power supply. Probably a bit better than what vacuum tube stuff typically used, though. \$\endgroup\$
    – Hearth
    Mar 28, 2023 at 23:07
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    \$\begingroup\$ (With a 2k2 series resistor, I'd put the 100 μF on the output side and about 22 μF as a load capacitor. Or use a 220 Ω load resistor and 2k series for lower peak current, still.) \$\endgroup\$
    – greybeard
    Mar 29, 2023 at 7:36

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