Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
----------------------------------------------------------------------
Steve -
Good point. Your personal voice characteristics have a LOT to do with
how a given mic will sound on the air. We seem to forget that the point
of communications radio is "communication" , not High Fidelity.!
Well, aside from some SSB types that think they're the next James Earl
Jones or Dick Clark.
The Drake transmitters are designed for "flat" frequency response
_within_ the ~ 2.4 kHz b/w of the sideband crystal filters. This
allows the user to tailor the audio to suit his/her voice by choice of
microphone (or external equalizer for the gadgeteers) to complement
their voice.
Most microphones have a relatively flat frequency response within the
audio passband. Some, especially the unamplified D-104, have a "rising"
characteristic that favors the upper voice range, which is where most of
the "intelligence" is contained. The problem with the D-104 and some
others is that they are VERY sensitive to the load impedance they see.
The D-104 is designed for a very hi-z input, I think around 1 Megohm.
The amplifier that was added to the D-104 serves two purposes. The
primary one is to provide a consistent 1M load to the microphone
cartridge, regardless of the transmitter input impedance. The amp also
enables the microphone to drive MUCH lower input impedances typical of
newer Low-Z audio stages in solid-state gear. Unfortunately, the
preamp is only mediocre, and while it does what it was designed to do,
it doesn't do it very well! There are a couple of articles on the
internet describing the addition of a JFET amplifier to improve the
operation. At least one that I have seen has an excellent discussion
with data on the frequency response of the D-104 with varying input
impedances. The JFET allows you to choose the input Z that favors your
voice.
I have used the D-104/amp, the Shure 444/D and E-V 664 with the 4 Line
and 7 Line transmitters with good results. The unamplified D-104 works
fine with my Globe King 500, and gets reports that I sound "just like I
do in person". I'm not sure if that's good or not........
73, Garey - K4OAH
Atlanta
Drake C-Line Service Manual
<http://www.k4oah.com>
Steve Berg wrote:
Steve Berg <[EMAIL PROTECTED]> made an utterance to the drakelist gang
----------------------------------------------------------------------
I cannot speak for anything about Drake transmitters, but I use 2 D104
amplified mics on my Ten Tecs and get great audio reports. I keep the
gain on the mic preamps low, and turn up the audio gain on the rigs.
I use an unamplified D104 with my Gonset GSB-100 phasing SSB exciter
and get great reports with that, even from the SSB-HiFI bunch on 40
meters. I have a very deep voice and the D104s seem to work fine for
me. I use a Shure 444 with my National NCX-5, and with the Icom
IC-202. They work well, too.
73,
Steve WA9JML
----------------------------------------------------------------------
Submissions: [email protected]
Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist
in body
Hopelessly Lost: [EMAIL PROTECTED] - help in body of message
Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net
----------------------------------------------------------------------
----------------------------------------------------------------------
Submissions: [email protected]
Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body
Hopelessly Lost: [EMAIL PROTECTED] - help in body of message
Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net
----------------------------------------------------------------------
