How to hear a power supply?

[glt]

Is there a way to determine if a PS is good enough by "listening" to it?. For example, I built a PGA2320 volume control and I used a PS from diyclub which is based on 7815 and 7915 regulators, further regulated with an opamp, I mute the inputs and crack the volume all the way up, and hear nothing. Is this a good test?... Thanks in advance for any ideas.

[TheMG]

The best way to measure output ripple, use an oscilloscope. Second best way, use a DMM.

[puginfo]

interested in the second best method. would you describe in detail of how to measure, pls.

thks

[TheMG]

Stick the DMM on "AC", and there you go. The lower the AC reading, the better. Any noise on your DC power supply will appear as AC on the DMM.

Problem with this is that the results are far from accurate using any cheap DMM. Using a "true RMS" DMM you get better results, but it will still not pick up on any high-frequency noise as DMMs tend to have a rather low frequency roll-off.

That is why the oscilloscope is the preferred method. Also it allows you to see the noise and therefore determine the nature and severity for troubleshooting purposes.

[Eric Juaneda]

Hi glt,

Originally posted by glt
Is there a way to determine if a PS is good enough by "listening" to it?. For example, I built a PGA2320 volume control and I used a PS from diyclub which is based on 7815 and 7915 regulators, further regulated with an opamp, I mute the inputs and crack the volume all the way up, and hear nothing. Is this a good test?... Thanks in advance for any ideas.

What do you search, a good sound or good ripple?
Your linear stage never sounds better than your power supply. Power supply's configuration is as important as circuits used in it.

LM317, understanding and listening

Eric