There are a couple of things that you could do:
1) An FET or bipolar transistor preamp on the mic output will
bring up the level of the existing mic element.
2) If you want to use an electret element, these are available from
many sources for 1 or 2 dollars. Yes, the DC voltage can be
piggy-backed on the audio line. In fact, most of the electret
mic elements have only 2 terminals, so this is what they do.
The terminal on the mic element that goes to the element case will
connect to shield ground. Inside the mic connector, connect a
1 k resistor between the output line of the mic element and pin 4
of the mic connector. This will bring in the + 4 V to the mic.
Now connect a 1 or 2 microfarad (uf) capacitor from pin 1 of the
mic connector to the junction of the mic output and the resistor.
This brings the audio into the rig. If you use an electrolytic
capacitor, connect the + side to the junction of the mic output
and the 1 k resistor. With an electret element, you will get plenty
of audio. Frequency response may be tailored somewhat by playing
with the value of the capacitor.
73, Bob WB2VUF
Arthur R Bernstein wrote:
>
> --------- Begin forwarded message ----------
> From: Arthur R Bernstein <n2ka@juno.com>
> To: TenTec@contesting.com
> Subject: [TenTec] TT 705 Cartridge in headset-boom mike??
To: <tentec@contesting.com>
> Date: Tue, 12 Oct 1999 01:33:27 EDT
> __Message-ID: <19991012.012351.4463.0.N2KA@juno.com>
> READ FOLLOWING (PREVIOUSLY POSTED MESSAGE). ANYONE HAVE ANY SUGGESTIONS
> FOR A REPLACEMENT ELEMENT FOR THIS HEADSET???????
> __________________________________________________________________
> Hi Group, I've just recently acquired a nice headset with a boom mike.
> It's an Azden HS-03. Unfortunately, I don't think these are readily
> available in the U.S. anymore, since Azden has stopped distribution of
> all their gear in this country. The microphone is attached to a thin,
> curved stainless steel tube through which a thin shielded mike cable
> runs. It appears to be single conductor shielded. I've noticed that the
> output from the mike element is not sufficient to drive my OMNI VI very
> well, even with the mike gain cranked way, way up (I'm familiar w/cranked
> up mike gain as I use the Heil HM-10 dual element mike.) The cartridge
> is approximately the diameter across of a quarter-it's a dynamic with a
> stated impedance of 500 ohms. No specifics given to voltage output.
> Frequency response is given as 300-4000hz w/ a 6db rise at 2500 hz,
> actually -10db at 300 hz (that's fine.) Was thinking of buying a 705
> element from Ten Tec and substituting it into the boom mike holder. The
> only problem I see is I believe the 705 is an electret and needs +4vdc on
> it, supplied by pin 4 on the OMNI VI. I dont think I could squeeze
> another wire into the mike boom tube tto get the +4v on the element. Is
> there another way to do this such as piggybacking the 4v on the audio
> line? How would this be done? Or would I have to run an external wire
> heat shrink tubed to the boom for the voltage.? This setup could be used
> with footswitch if I wire in a
> jack to mike connector between pin 3 and ground.-as Heil does.
> Any suggestions or ideas?
> Thanks in advance.
> 73,
> Art, N2KA.. (95% CW!!!)
> ___________________________________________________________________ Get
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> --------- End forwarded message ----------
>
> ________________________________________________________________
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