Multi Voltage PSU +/-15V +/-24V +48V +5V [pics/updates]

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Hi
I wanna make one psu for preamp who have bipolar +/-16VDC, +48VDC and -37VDC.
Can I do it like this
Tapco_psu_317.GIF

or, must do it like this
Tapco_psu_337.GIF

Or, its the same, except I am wrong :)
Thanks
Duka
 
Hi Duka,

both will not work as drawn, but the 2nd one is easier to fix. (1st will also need a separate transformer secondary winding, and this being a custom built transformer, you order to your requirements and can get away without these voltage doublers)

Your -37V parts should also have another index than the upper +48V parts.

The lower (-37V) caps C5+C6 are polarity reversed.nonsense
For the lower (-37V) R10 trimmer as drawn make sure, this part is rated for at least 0.5W or use a 3K3/0.5W and 250R trimmer in series.
What's the connected load to this part?

As drawn, your wanted +/-16V supply you might measure +/- 12.7V. Maybe increase R6+R8 to 1K4 or use a 1K2 with 500R trimmer in series for a 13.75V to 18.95V range with your 16V target voltage at center.

With upper (+48V) current setting resistor R9 @ 120R for ~10mA, this 4K5 resistor has to stand 0.49W, so better use a 1W part.
 
Hi Harpo
Thanks for answer. I agree with some corrections about resistors and trim value. I just redraw schematic above and add needed -37V rails. Too I made many similar psu for my project (without added trace) and it works. I was thinking, because we use unregulated AC, there is posibility to get negative voltage after similar circuit like we didi it in a case of +48. Second, I wanna make with one bigger trafo what I have.
Thanks
Duka
 
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