[Elecraft] KX3 headphone output impedance and recommended speaker

[w0jx at yahoo.com]

I searched the KX3 manual and could not find a specification for the headset/speaker output jack. Last weekend at Field Day I plugged in a low impedance speaker and got some oscillations above a certain output level.

I want to optimize the impedance match to my computer for FT8 and also know what speaker impedance would be the best match for my KX3.

Also, what would be the preferred after-market amplified speaker for the KX3?

73, Dennis W0JX