[Elecraft] K3S audio quality issue

[Mike Kholodov]

 Listening to the K3S audio had become very fatiguing for me as of late. It sounds like hum or carrier is mixed in at the low end. It is very similar to the sound, if you tune a little bit higher on USB. I checked the same stations on my KX3, they sounded great. Used the same headphones in both cases. Has someone had the similar problem and is there any solution before I request the official support?
Thanks,Mike, AB3VN