Great Article On AC Power Harmonic Issues

imfree707 · 24th January 2011, 02:17 AM

Hi Guys, here's a great article about AC line harmonic related issues.

http://www.conceptorg.com/techlibrar..._and_Audio.pdf

I found the article while doing research for my VLF interest. AC line harmonics and noise cause severe interference and make VLF Natural Radio Listening difficult-to-impossible in most homes. VLF Natural Radio is audio, so this article is relevant for Audio DIYer's, tas well.

zigzagflux · 24th January 2011, 03:27 AM

I'm not seeing any earth-shattering recommendations in this article. A whole bunch of preliminary symptoms and causes, with recommendations that are entry level at best. Connection order in the power strip, tight connections at the outlet, and not crossing wires? That's it? There are much better ways to address harmonic problems.

The conclusion is anecdotal, with absolutely no analysis. Not a very worthwhile article IMO.

DF96 · 24th January 2011, 11:56 AM

7 1/2 pages. 6 pages on how electricity is generated and used (presumably the writer's day job?). 1 1/2 pages on elementary precautions. The useful stuff could have been said in 1 page. Mains filters mentioned almost in passing, after lots of stuff about fancy power cables.

Was this article actually a marketing tool for the author's consultancy business?

metalsculptor · 25th January 2011, 07:34 AM

Good article with respect to the power distribution side but it appears to be very selective with the interference side of things.

For example he mentions the notching effect of a cycloconvertor but fails to name it, these devices are rare now. Then he goes on to mention lots of harmonic standards but fails to relate that to actual distortion at the outlet or more importantly the audio equipment supply rails.

Furthermore he mentions the effect that a transformer based PSU might have on the supply but doest not include transformer impedance in the analysis or mention how that relates to noise in either the amplifier in question or adjacent sound equipment.

Transformer based PSU's are very good at filtering harmonics with better than -6db per octave rejection of harmonics over the fundamental in most cases. of course the harmonics are more audible than the fundamental dues to the ears response.

24th January 2011, 02:17 AM	#1
imfree707 diyAudio Member Join Date: Oct 2010 Location: Tenn Loop Ranch, Lebanon, Tn.	Great Article On AC Power Harmonic Issues Hi Guys, here's a great article about AC line harmonic related issues. http://www.conceptorg.com/techlibrar..._and_Audio.pdf I found the article while doing research for my VLF interest. AC line harmonics and noise cause severe interference and make VLF Natural Radio Listening difficult-to-impossible in most homes. VLF Natural Radio is audio, so this article is relevant for Audio DIYer's, tas well. __________________ A stiff power supply in a great-sounding amp is always better for you than a stiff drink.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Great article on Fonken Full-Range	JesseG	Everything Else	0	12th June 2007 09:44 PM
Great Vandersteen article	David Gatti	Multi-Way	30	19th March 2006 04:50 PM
Height issues for Dayton CSS AC 3way	dunderchief	Multi-Way	7	11th February 2005 07:30 PM
Hack or tinker ? -- a great article !	jackinnj	Everything Else	2	7th September 2004 07:16 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

24th January 2011, 03:27 AM	#2
zigzagflux diyAudio Member Join Date: Oct 2006	I'm not seeing any earth-shattering recommendations in this article. A whole bunch of preliminary symptoms and causes, with recommendations that are entry level at best. Connection order in the power strip, tight connections at the outlet, and not crossing wires? That's it? There are much better ways to address harmonic problems. The conclusion is anecdotal, with absolutely no analysis. Not a very worthwhile article IMO.

24th January 2011, 11:56 AM	#3
DF96 diyAudio Member Join Date: May 2007	7 1/2 pages. 6 pages on how electricity is generated and used (presumably the writer's day job?). 1 1/2 pages on elementary precautions. The useful stuff could have been said in 1 page. Mains filters mentioned almost in passing, after lots of stuff about fancy power cables. Was this article actually a marketing tool for the author's consultancy business?

25th January 2011, 07:34 AM	#4
metalsculptor diyAudio Member Join Date: Sep 2010 Location: Melbourne	Good article with respect to the power distribution side but it appears to be very selective with the interference side of things. For example he mentions the notching effect of a cycloconvertor but fails to name it, these devices are rare now. Then he goes on to mention lots of harmonic standards but fails to relate that to actual distortion at the outlet or more importantly the audio equipment supply rails. Furthermore he mentions the effect that a transformer based PSU might have on the supply but doest not include transformer impedance in the analysis or mention how that relates to noise in either the amplifier in question or adjacent sound equipment. Transformer based PSU's are very good at filtering harmonics with better than -6db per octave rejection of harmonics over the fundamental in most cases. of course the harmonics are more audible than the fundamental dues to the ears response.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)