Shielding, on further investigation

[William Walker <billwalker@baymoon.com>]

Now my head really hurts, I tried some more tests to recreate the  
weird hum i was experiencing and realized the two instruments that  
were susceptible where the two with duncan mag mic active pickups in  
them, which also brings up the possibility that an aging 9 volt  
battery might be also culprit.  Put if that were the case I'd probably  
here the high pitched whine regardless of whether I was looping or  
not. The difficulty is that it might be a number of things happening  
to cause the problem. One thing I did try the last time this happened  
was to put a buffer amp in the signal path which also cured the issue.  
Puzzling .. weird, ghosts in the machine........ And then again its  
probably just the ancient overworked electrical system in our  
house................
Bill