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