As mentioned above, 50/60Hz hum is probably more to do with an earthing (ohmic--current loop etc) problem. I rechecked my electrical theory on Wikipedia. A short article covers it fairly well there:
http://en.wikipedia.org/wiki/Electromagnetic_interference A relevant extract is as follows: "The efficiency of the radiation is dependent on ..... the length of the conductor in relationship to the wavelength of the signal component (fundamental, harmonic or transient (overshoot, undershoot or ringing). At lower frequencies, such as 133 MHz, radiation is almost exclusively .....etc etc" Thus EM pick up is related to 'ariel' length. As electricity flows nearly at speed of light (3x10^8 m/sec), the wavelength at 50Hz = c/f = 6 kilometers. A hell of a long ariel. Note the discussion of 133MHz called "lower frequencies"... Dan -- chinablues ------------------------------------------------------------------------ chinablues's Profile: http://forums.slimdevices.com/member.php?userid=7955 View this thread: http://forums.slimdevices.com/showthread.php?t=34279 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
