On a sunny day (Thu, 22 Feb 2007 01:54:17 -0500) it happened "John Gilmer"
wrote in :


"**THE-RFI-EMI-GUY**" wrote in message
.. .
Please! I hope you mean to have this buffered through an isolation
transformer!

Why should he?

It's the equivalent of use a "scope" probe to look at line voltage. The
"danger" is at the probe tip but not at the end going to the scope.

There is a little catch here.
The PC case is normally connected to mains ground, and we want the quality
of the line between zero and phase, then without a transformer we also grab
all the noise and stuff between ground and zero.
That could show some peaks in some cases..



R1 |
---------------------- live --------===------------------------| soundcard line in
| |
[ ] R2 |
|____________| soundcard ground
--------------------- zero------------ not |
connected |
|
| PC case
--------------------- ground (safety) -------------------------|_____________