Chris, A simple voltage divider *may* be required, but I would suggest trying it without any attenuation first. It all depends on where the soundcard controls the microphone gain - be on the lookout for overload in the soundcard, and if present, add an attenuator. A series resistor may work just fine, or as you suggest, a voltage divider.
Impedance matching is not necessary nor desirable. Audio devices operate well by using a low impedance source (able to provide more driving current than is required) and a high impedance sink (which will limit the current drawn). The characteristics of the sink (in your case, the microphone input) will determine how much current is drawn from the source (the K3). An analogy is to consider utility power wiring - the outlet receptacle provides a very low impedance source, and the device that you plug into that wall socket will determine how much current is drawn, therefore the amount of power that is transferred from the power company to your device. Within limits, an audio source/sink combination works the same way, but the actual source impedance will not be as near zero as the power company source, it will have some finite value such that if the current drawn is too large, distortion products will be developed in the driver. When the available source power is near the power to be dissipated (as in a transceiver/antenna situation), then impedance matching becomes important for maximum power transfer - because the source power is limited (or more correctly, not vastly greater than the power required by the sink). 73, Don W3FPR Chris Meagher wrote: > Hello, > > I want to connect K3 audio line out to a Toshiba laptop which only has a 3.5 > mic socket for audio in. > Does anyone have recommendations for attenuation/impedance matching? > I was thinking of a simple votage divider. > > Thanks, > > Chris VK2LCD > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.287 / Virus Database: 270.12.8/2086 - Release Date: 04/29/09 > 06:37:00 > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
