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PS Audio line filter
I think you are right to make this yourself, and not spend $200-300 to try it out. This type of high-current device can reduce some types of noise, but the claims made for it seem as exaggerated as the price.
Regarding the article, it seems to me that anyone who reviews audio equipment, and at the same time can't be bothered to chase down the "...slight hums and buzzes I sometimes hear in my system..." should not be taken too seriously. There should only be an audible effect if in fact you have a problem with noise that you know affects your gear.
Up to about 2-3A, you could also try a Panasonic line of common mode chokes designed for line filters:
http://www.panasonic.com/industrial/components/pdf/el059_elf_v_h_f_m_n_highn_dne.pdf
Panasonic has thoughtfully published the impedance curves in the same document, and the parts are available from Digikey.
PM
I think you are right to make this yourself, and not spend $200-300 to try it out. This type of high-current device can reduce some types of noise, but the claims made for it seem as exaggerated as the price.
Regarding the article, it seems to me that anyone who reviews audio equipment, and at the same time can't be bothered to chase down the "...slight hums and buzzes I sometimes hear in my system..." should not be taken too seriously. There should only be an audible effect if in fact you have a problem with noise that you know affects your gear.
Up to about 2-3A, you could also try a Panasonic line of common mode chokes designed for line filters:
http://www.panasonic.com/industrial/components/pdf/el059_elf_v_h_f_m_n_highn_dne.pdf
Panasonic has thoughtfully published the impedance curves in the same document, and the parts are available from Digikey.
PM
Strikes me as a lot of work to build your own corcom filter. It would be interesting to see how your filter compares to an off the shelf corcom filter.
your little board looks quite nice BTW.
Sheldon
your little board looks quite nice BTW.
Sheldon
Re: PS Audio line filter
I've got two of these chokes lying about. How exactly can I use them for the AC filtering? Any circuit desings you can point to?
PMiczek said:
I've got two of these chokes lying about. How exactly can I use them for the AC filtering? Any circuit desings you can point to?
Look for AN-20 under app notes on this site, as well as some other interesting info about noise sources noise suppression, transformers and power supplies. It has a good explanation of how these filters work, the difference between common mode and diff mode inductance used in power supply lines, etc. Also some sample circuits and component values.
http://www.powerint.com/appnotes.htm
Only some of this applies to audio, but noise and other types of distortion from the power line can show up on your ps lines. Audio designs often use multiple transformers, and some strange things can happen when noise from outside the box finally shows up on a common ground with different secondaries connected, so there is another entire level of complicating effects to be considered.
In a different thread here, I posted a question about using these filters (common-mode choke and cap filters) on power lines in high-end audio. Not sure if the Q was really understood, but responses ranged from "I like them in some applications", to "They suck, big time." While the noise suppression can be calculated, I would not discount the "suck-big-time" opinion out of hand either, even if you cannot attach a number to it. Take your pick.
PM
http://www.powerint.com/appnotes.htm
Only some of this applies to audio, but noise and other types of distortion from the power line can show up on your ps lines. Audio designs often use multiple transformers, and some strange things can happen when noise from outside the box finally shows up on a common ground with different secondaries connected, so there is another entire level of complicating effects to be considered.
In a different thread here, I posted a question about using these filters (common-mode choke and cap filters) on power lines in high-end audio. Not sure if the Q was really understood, but responses ranged from "I like them in some applications", to "They suck, big time." While the noise suppression can be calculated, I would not discount the "suck-big-time" opinion out of hand either, even if you cannot attach a number to it. Take your pick.
PM
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