On Mon,2/6/2017 6:35 PM, Don Wilhelm wrote:
One of your big problems is that the speaker specified in that project is 8 ohms - if you can find a 4 ohm speaker, you will almost quadruple the available audio.
Not quite. A loudspeaker amplifier is essentially a constant voltage source. If the two speakers have the same efficiency, the 4 ohm speaker will be 3 dB louder. But all speakers do NOT have the same efficiency, and Elecraft has been good at choosing small speakers with high efficiency for their size.
That speaker in QST is a cute idea and demonstrates the principle of an acoustic filter. That's the value of it.
The KX2 and KX3 are carefully designed to maximize battery life for portable operation. Part of that careful design is to limit the current in the audio output stage. It's really designed for headphones, or with external amplified loudspeakers.
BTW -- I think the original question about the output being "padded" is a reference to a passive attenuator -- a resistive voltage divider. In the audio and broadcast world, components or networks like this are called a "pad."
No, the output of these radios are not padded in that sense, but it is good practice to add a small resistor in series with the output of any audio power amp that connects to a jack, so that it's less likely to be damaged when a jack is partially inserted and shorts the output. :)
73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
