[Elecraft] Audio feed back (I think?)

[GD0TEP]

Hi to the group,

I have connected my K3 to my PC so I can use WSJT, my sound card is the
'Sound Blaster Audigy 2 ZS Audio'

I seem to have some sort of audio feed back when I get the radio to TX.

The sound card output is directly connected to the K3, and for the moment
PTT keying is via a USB micro ham unit.

When I use the microham device router to test the system by TXing a test
signal (standard single tone) all 'appears' to be OK, but, what I hear (from
the monitor in the K3) is a little distorted, and this distortion gets worse
the higher the MON is set at (currently at 10) once MON goes higher than 15
or 16, I can hear distortion.

I thought it was perhaps an issue with the sound card, so I've tried the
'built in' card on the PC and there's no difference.

My next thought is that it's a setting I'm missing within the K3, but I
can't see what...

MON = 10
LINE = 36 but altering this doesn't affect the signal distortion

There also appears to be a delay in sending tones from WSJT, I'm sure that
this is a software issue, but in this delay there's about a second of what
can only be described as hash.  

Anyone got any suggestions on what I can check next??

73,
Andy
http://gd0tep.com