BG>>P.S> Thanks for your comments. I intend to support this echo as long as
BG>>there remains a Fidonet.. There's getting to be a number of folks that
BG>>have experienced newsgroups and are coming back to the echos because
BG>>they suit them better. Something like how vinyl is making a
BG>>retrocomeback for some people.
>     I've heard from people who say that Usenet has more variety, but
>     the signal has slowly disappeared into the noise.  Moderated
>     conferences _are_ better.
I get a lot of callers to my BBS go and visit the internet and then 
start calling back again...
Anarchy is great but just keep it over -there- somewhere please... 
>     I enjoyed your essay on ground loops, but I'm still perplexed.
>     A few years ago I built a surprisingly good hi-fi preamp by cobbling
>     together some op-amp circuits from a Walter Jung book.  In the
Jung is a master!
>     matter of grounds, I took every ground I could think of, from
>     chip grounds to cable grounds to any old grounds, and tied them to
>     a single rail.  I've never tested this preamp with really esoteric
>     equipment, but as far as I can tell the hum is inaudible.
>     Did I done good, or is there a better method?  Should the 'star
If it is inaubdible, then you "done good"  If you were designing a 
power amp, the ground would have to be a little bit more scientific
since you are carrying some large currents and can produce quite a 
voltage drop over a few inches of wire.
>     ground', chassis and all, be connected to the third wire on the AC 
>     cord? I think the smartest thing I did for reducing hum was to put the
>     AC transformer in a separate box in the back of the preamp.
>     The only 60Hz AC in the main area is about 3 inches of +20 and
>     -20V AC from the transformer.
That is the secret! Also, beyond grounding issues, the electromagnetic 
field from a transformer can induce current flow in wires placed near 
it.  This can be maddening to trace out. Another one I personally ran 
across was a small transistor with a bubble in the case.  Let just
enough light through to cause a small hum.  Took the cover off and
it got worse...  Took about 20 minutes to figure it out!  
If you are looking for basic books on analogue design and 
troubleshooting, get Bob Pease's Troubleshooting Analog Circuits. It 
is available in paperback and is worth every penny of it's price.
Best to check a local school library first to see if they have a copy 
but it is a good one to have on your reference shelf...
--- Via Silver Xpress V4.4 [Reg]
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