From: jasen@xnet.co.nz   
      
   On 2009-02-21, Stoatgobbler  wrote:   
   > Hi there,   
   >   
   > I'm building a JL Hood hifi amplifier and to construct the power   
   > supplies I've mounted two toroidal transformers in a case, one on top of   
   > the other. Each toroid has two secondary windings which I'm going to use   
   > to create two separate, independent, regulated +22v - 0 - -22v power   
   > supplies. To make these power supplies truly independent (and to reduce   
   > the chances of earth loop hum) I've "lifted" each power supply 0v common   
   > from the chassis earth via 60ohm resistors.   
   >   
   > On testing the power supplies I've noticed that the greater the current   
   > I pull out of each power supply the greater the potential difference   
   > that appears across the 60ohm resistor (chassis earth to power supply 0v   
   > line). when I pull 1.1A from the power supply then I have nearly 17v   
   > across the 60ohm resistor. This voltage does not seem to vary with   
   > raising the upper toroidal away from the lower so I don't think the size   
   > of this voltage is to do with interactions between the two (but would   
   > stand to be corrected).   
   >   
   > I've never "played" with this, I did expect a voltage across it (due to   
   > eddy currents within the transformer normally "lost" in heating the iron   
   > core in a conventional E I type transformer?) but I thought toroidals   
   > minimised this and the voltages resulting from this would be   
   > nominal....17v across 60ohm is not nominal.   
   >   
   > Is this normal or is something going on?   
      
   somethings going on.   
      
   AC or DC ?   
   frequency?   
      
   > Any advice or comments would be appreciated.   
      
   can't make any usefull guesses without knowing what it was and what   
   you've done to it.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)