[at-l] Off topic - Audio question

[Jim and/or Ginny Owen]

skeeter wrote:>The radio reception where I live is lousy, so I have the computer tied into>the stereo so I can use on-line radio.>To do this I have a splitter (so I have the computer speakers wired in too,>the stereo is in another room), and then a RCA left/right channel jack>plugged into the splitter. With all these jacks plugged one into another I>can't believe that I'm picking up a 60Hz hum someplace ;  )>Does somebody have a more elegant solution than what I have?Long ago and far away we had the same problem with spacecraft.  At one point (mid-60s) we 
had a spacecraft isolated from the 60-cycle and the base-level 60-cycle AC voltage was well 
over 100 volts although with very little (low milli-amp range) current flow. Grounding the 
spacecraft frame eliminated the problem, but it doesn't always work that easily. Somewhere 
I still have the book that that incident generated. A whole new engineering discipline (EMI) 
came out of that. 
 
You have the same problem we had - an ungrounded system that's reflecting the ambient 60 
cycle of the house current. Putting it through the stereo probably amplifies it so it's audible.  
One  solution is to ground the system - probably at the shell of the splitter, although that's 
only a guess on my part.  Another solution might be to go wireless.  That would be more 
expensive, although (maybe?) more elegant.  
 
Good luck - let us know what happens,
Jim
http://www.spiriteaglehome.com/
 
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