[Elecraft] QSK Thump on KX-1

[Jeff Imel]

My KX-1 is serial number 32.  It was built this week and it is a lovely rig.  I do have a problem with QSK thump.  I am wondering if any of you have experienced this and I am interested in learning what you did to correct it.

It thumps when it goes from transmit to receive and the receive audio slowly comes back up to normal after about a half of second.  It does not do it all the time, only after I have been sending for about a minute.  Once it starts thumping, it will continue to thump until I cycle power.  Sometimes that removes the thump, sometimes it doesn't.  I have tried using three different antennas with and without an external tuner and nothing removes the QSK thump.  I experience QSK thump on all bands.

Any ideas?

Thanks and 73

Jeff
KB9ZUR