Measuring Noise
For LED's - Christer's thread https://www.diyaudio.com/forums/parts...er-diodes.html
An interesting method of grading zeners for noise, that I have used for years, is to monitor the noise across the devices with a scope while using my HP bench supply to bias them. The noise spectrum changes quite dramatically as you come into breakdown and then drops to it's minimum at it's prefered current flow. I note the current and voltage after it has settled down. I choose the ones to use by voltage match and bias them accordingly.
One other trick, if you want to know how quiet your supply is, choose a suitible coupling cap and hook the output of it up to a line input on your preamp and listen to it. Try this with and without a load and during normal operation of the supply. A good supply is dead quiet. author: MikeBettinger
An interesting method of grading zeners for noise, that I have used for years, is to monitor the noise across the devices with a scope while using my HP bench supply to bias them. The noise spectrum changes quite dramatically as you come into breakdown and then drops to it's minimum at it's prefered current flow. I note the current and voltage after it has settled down. I choose the ones to use by voltage match and bias them accordingly.
One other trick, if you want to know how quiet your supply is, choose a suitible coupling cap and hook the output of it up to a line input on your preamp and listen to it. Try this with and without a load and during normal operation of the supply. A good supply is dead quiet. author: MikeBettinger
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Comments
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Yep, good idea! I do the same thing with a DC blocking cap and headphones to listen to the PSU. If it's really quiet, your method would be better - more sensitive.Posted 9th July 2012 at 01:49 AM by Pano
