Hi, all.

I have noticed something when using my TS480 with my 35-amp Samlex switching 
power supply.

When I transmit with 100 watts, in CW mode or in RTTY mode using the stock 
mic, I notice a slight but audible hum coming from the switching power 
supply.  The hum stops when I stop transmitting.  I had my XYL take a look 
at the meters on the front of the supply, and they say I'm running at 13.8 
volts, and drawing about 19 amps, which is about what I'd expect.

And, just for the record, I'm doing this with a resonant antenna, and just 
using the auto-tuner to be sure I have a perfect match.

Is this slight but noticeable hum when transmitting normal?

Thanks, and 73 from Tom Behler:  KB8TYJ