[Amps] odd problem with Henry 5K

[Louis Parascondola]

Had a friend ask me about an odd problem with a Henry 5K running a pair of 3CX1200A7 tubes.  Since 10 meters has been opened he has been using it.  He discovered what he called a "birdie" type signal on his radio when receiving on 10 meters.  Said he heard it spaced every couple of KHZ as he tuned around the 10  meter band.  At first he didn't know what it was hut said he traced it to the 5K amp.  he said if he detuned the load or tune on the amp the signal went away.  He said it only appeared when the amp was properly tuned up for 10 meters.  The amp was just on, not in transmit,  just on and he heard the signal.  Detune it and its gone.  Ideas?  Does not happen on any other band.