I like a microphone that has proper level and response so I don't need to run gain up near full open and works with any rig without cranking the lows up ten or 15 dB, thus the reason the reason my D104 has a source follower that makes the mic output Z lower than the radio input Z so it appears as a voltage source.
:-) ----- Original Message ----- From: "Jim Brown" <j...@audiosystemsgroup.com> To: <elecraft@mailman.qth.net> Sent: Saturday, July 10, 2010 12:20 AM Subject: Re: [Elecraft] D104 mic > On Fri, 9 Jul 2010 20:47:36 -0400, Tom W8JI wrote: > >>It will sound great if you add a J310 or similar JFET source follower. > > Hams spend WAY too much time hand-wringing about impedance matching in > audio circuits. Audio circuits have not been impedance matched for > nearly 50 years! As long as the input Z of the preamp is not so low > that it loads the mic severely, everything should be fine. The input Z > of the K3 mic circuit is on the order of 10K. That's pretty high, and > most mics ought to be quite happy with it. > > For a passive mic, the downside of excessive loading is usually some > modification of the frequency response, some loss of level, but no > distortion. TXEQ can easily fix any response problems, and the K3 has > plenty of mic gain to make up for any loss. > > Tom's advice is solid if it's a VERY high Z mic, BUT it may also depend > on the version of D104 that you have. I haven't played with a D104 for > nearly 40 years, so don't know enough about that to have an opinion > that matters. :) I would first try it straight into the K3 as Hank did, > adjust levels per Elecraft intructions, then get someone with good > audio ears to talk you into TXEQ settings on the air. If you can't make > it sound right, then follow Tom's advice and build the follower > circuit. > > 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 ______________________________________________________________ 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
