Chris, Unmodified, it will probably sound terrible (very 'bright with lots of highs, weak lows), but with a bit of work, it will sound great - just like Astatic intended. The D-104 element is either crystal or ceramic, and wants to work into a high impedance (like the grid of a vacuum tube with a 1 megohm 'grid leak' resistor) load. Modern transceivers present a much lower impedance load (nominally 600 ohms).
I have seen some comments that the simple insertion of a 1 megohm resistor in series with the AF line is all that is needed. That may be the first thing to try. I strongly suggest you use the K3 monitor function with the K3 in TEST mode and record your audio on the computer - listen to the recording to see what it sounds like (that is almost impossible to judge while listening With a single FET buffer or an op amp between the D-104 and the K3 (or any other transceiver), the D-104 will "come to life" just as it did with the old vacuum tube rigs. An op amp solution is a natural because the characteristic of an op amp is very high input impedance and low output impedance - perfect for the D-104. An LM358 wired as a unity gain buffer should do the job nicely, and for the voltage swings involved (small) the LM358 can be powered from the +8 volts available at the front microphone jack pin 6. If you would want to use the rear microphone jack, the FET solution would be better because the voltage to drive the FET can be supplied by turning bias on. I am not going to give you a circuit diagram because I have not developed and tried it out. There is another solution - that is to replace the original element with an electret element, or with a Heil HC-4 or HC-5 element (Heil offers a kit for that). 73, Don W3FPR Chris Hembree wrote: > Anyone ever use a D-104 (non amp) on a K3. How does it sound? > Chris W7CTH > > ______________________________________________________________ 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
