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| Small and quite +/-8v power supply/regulator |
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| iMo:
There are hundreds of posts on LM317/LM337 noise at, for example, the diyaudio forum. The 240uVrms somebody here posted comes from the DS (ie. TI), where it states the rms value (10Hz to 10kHz) is 0.003% of the output voltage. With a blocking capacitor at the divider the noise is much lower, for detailed measurement results please read the above forum, for example. |
| Gyro:
@CuriousAbe: You could usefully add a 10nF ceramic cap across each of your rectifier 1N4004s (CR1 and CR2) to snub any recovery induced switching noise. In sensitive audio circuits, this can manifest as a twice mains frequency low level buzzing. |
| mariush:
--- Quote from: imo on July 27, 2019, 06:04:29 pm ---There are hundreds of posts on LM317/LM337 noise at, for example, the diyaudio forum. The 240uVrms somebody here posted comes from the DS (ie. TI), where it states the rms value (10Hz to 10kHz) is 0.003% of the output voltage. With a blocking capacitor at the divider the noise is much lower, for detailed measurement results please read the above forum, for example. --- End quote --- LM1084 advertises the same 0.003% of Vout RMS output noise (page 6): http://www.ti.com/lit/ds/symlink/lm1084.pdf If you don't mind less than 200mA of current, an option may be ADP7118 with 11uV rms : https://www.digikey.com/product-detail/en/analog-devices-inc/ADP7118ACPZN-R7/ADP7118ACPZN-R7CT-ND/6568642 |
| CuriousAbe:
Thanks for all the help and useful suggestions! I will probably go with some variation of below since it seems pretty much perfect for what I'm after: https://www.diyaudio.com/forums/power-supplies/340731-lm317-lm337-power-supply-pcb.html |
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