The HW101 puts the speaker and whatever is plugged into the headphone
jack in series. When nothing is plugged into the headphone jack, the
contacts in the jack directly ground the jack side of the speaker.

So, if you use high impedance headphones, you will still get a little
mumble out of the speaker, but not very much.

-Chuck

JOHN D wrote:
Can I expect speaker to mute completely if I use high impedance 2k ohm
headphones?
I still get some sound from the speaker.
I even plugged in a spare unwired phone plug.and still got speaker sound.
It looks to me like that should have created a open circuit to the speaker.
Is this normal or is something wrong with this thing?
I was trying to get out of rewireing it for low impedance phones