[Elecraft] KX2 WTB(uild) external amplified speaker

[Andrew Moore]

KX2 arrived yesterday after a ~15 week wait, which was pretty much spot on
with Elecraft's original estimate.

One of the best features is, especially for a compact rig with limited
dedicated controls, the ability to assign a programmable function button to
an otherwise buried menu feature. For menu features that are binary choices
(such as enable/disable CW transmit), not only does the PFn button activate
the menu item, but it also toggles the parameter and dumps you right back
into operating mode. For example, you can toggle between "CW transmit" and
"CW practice (no transmit)" by pressing only two buttons. No need to go
through deep menus. Kudos to KX2 designers for thinking ahead.

One of the not so great features is the internal speaker. It's even raspier
and more distorted than the forward-facing one supplied with the KX3. This
is to be expected; there are design trade-offs and this rig wasn't designed
to be a desktop model with high wattage audio output.

My typical use case for the KX2 is to listen to it in the background on the
desktop with good quality speaker audio, and then to switch to
headphones/earphones when in QSO.

So I'd like to build an audio amplifier to convert the KX2 headphone output
levels to say 5 watt speaker output (one of the two channels will suffice)
for listening to relatively undistorted audio in the shack. A good starting
point is knowing what the output level and impedance is for the headphones
jack. I measured approx 20 mV P-P (impedance unknown) at an audio output
level around "AF 10" according to the KX2 display. Does this sound about
right?

Bonus points: First QSO with the KX2 was from Maine to Bermuda at 1 watt.

Thanks,
-Andrew NV1B
..