Just got a new set of mics and just did a quick sound check on them. I recorded a grand piano and noticed a discernible hum, especially at the end while the last note faded. I need to do some more tests but wanted to know if, simply, mic orientation might be the culprit. I don't want to mention the mics just yet as I might post some sound samples here later. I will say that I'm recording into a Marantz 661 with phantom power, and no pre.
Thanks for your input.