On 1/13/2012 9:20 AM, Phil Hystad wrote: > Unfortunately, it is in both mics but not as strong in the Yamaha CM500 mic > as in the MH2 but it is present.
Clarification question. Is it HUM (pure 60 Hz), or BUZZ (mostly harmonics of 60 Hz)? If it's HUM, I would suspect magnetic field coupling into the audio, either from a big power transformer (like the one in a power amp or a big linear power supply) or from a AC power wiring fault called a double-bonded neutral. The K3 has unshielded audio transformers at all the audio inputs and outputs, and an unshielded transformer is a sitting duck for magnetic fields. The good news is that the K3 has excellent audio equalization (TXEQ) that allows us to remove that 60 Hz hum by filtering. The lower audio frequencies in the human voice make NO useful contribution to speech intelligibility, but they do waste transmit power. So it is ALWAYS a good thing to set the TXEQ for maximum cut of the lowest two bands, and at least some cut of the third band. This is true with virtually ALL mics and ALL voices. AND it will reduce that hum enough that you may no longer hear it. There are several solutions to magnetic field coupling. 1) Rotate the noise source or the victim circuit to put the fields at right angles to the victim. 2) Move the noise source further from the victim. 3) If the hum field is produced by that AC power wiring error, fix the error to eliminate the field. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
