[Phil Allison[_4_]]

mcp6453 wrote:



I'm still not clear on the source of the noise. However, it's safe to
say that the noise is electromagnetic. I found a couple of like-new EV
N/D 767a mics at my local Guitar Center for $69 each, so I bought them.
They have humbucking coils in them and are totally quiet.


** The correlation between having a humbucking coil fitted and being noise free in the office room appears 100%.

The odds are high that an adjoining room or one above or below is used for AC power distribution, is fitted with high current cabling and a switchboard.

Wherever Active and Neutral conductors travel separated rather than running in close parallel, the external magnetic field generated is much greater than usual - easily enough to cause the hum interference you have described.



..... Phil