JohnSwenson;574856 Wrote: > While I agree that some of these prices are ridiculous, this argument is > not a very good one. This is assuming that the only thing a power cord > can affect is what is coming in from the wall into the device. > Frequently this is not the case. > > I have done a lot of experimentation on this and find that a very large > percentage of sound changes due to power cords are the effect the cords > have on the transformer resonances in the box. > > Almost all transformers have fairly high Q resonances in the ultrasonic > area, right where switching supplies and silicon diodes emit noise, thus > stimulating these resonances. This ultrasonic noise can wreak havoc in > many pieces of equipment. > > The power cords are an important part in determining the resonance > frequency and Q of these resonances. > > Not only does the result of these resonances cause problems in the > device the cord is plugged into, but it can also travel through the > cord into other boxes, stimulating THEIR transformer resonances. (this > is not wild fancy, I have measured this many times) > > The net result is that a power cord CAN have a significant affect on > the sound of a stereo system. The problem is in correlating it to > anything. Since each system is different with different combinations of > transformers its very difficult to make recommendations as to which cord > design is going to be "better" than another. An expensive cord may very > well sound better than a cheap one, but it may also sound worse. > > The best way to deal with this is to damp the transformer resonances in > the boxes themselves, its not hard to do, but hardly any manufacturers > DO it. I think primarily because nobody knows its a problem. Its a > significant affect that for some reason seems to have completely flown > under the radar of the audio design community. > > So you can either damp the transformers in all your boxes, OR spend > time playing with different power cords until you find a combination > that reduces the resonance affects. > > BTW these resonances are electrical, NOT mechanical, rubber washers and > the like isolate mechanical resonances not electrical ones. > > So there you have it, I have measured significant differences in audio > systems due to power cords, but I have not been able to come up with > any decent correlations as to what type or design is any better at > reducing the noise. > > John S.
This is extremely enlightening! Is it ok to quote this on other audio fora when the subject of power cord discussions come up? -- konut ------------------------------------------------------------------------ konut's Profile: http://forums.slimdevices.com/member.php?userid=1596 View this thread: http://forums.slimdevices.com/showthread.php?t=78938 _______________________________________________ Touch mailing list Touch@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/touch
