[Elecraft] [K3] Headphone imbalance

[Barry]

Odd, minor problem, wonder if anyone has any insight:
I have my headphones plugged into the back and leave them there all the 
time.  When I want headphones only, I use a prgroammed macro in PF1 to 
turn off the speaker.  When both speaker and headphones are on, and I'm 
wearing the headphones, the left ear is significantly louder than the 
right ear.  When I turn the speaker off, both ears are balanced.  The 
headphones have a 16 ohm impedance.  Any ideas?
Tnx,
Barry W2UP