[TenTec] microphones and ten tec gear

Bob & Linda McGraw K4TAX RMcGraw@InfoAve.Net
Sat, 12 May 2001 17:10:47 -0700


On the other hand, a mike like the D-104, using a crystal element has a
very high Z demand for its load.  The question then becomes is 10K ohms
high impedance or is 100K ohms high impedance.  Most designers today
make the assumption that 10K is Hi-Z while <600 ohms is Lo-Z.  D-104's
typically don't like either of these and the high frequency response is
the first to go.  The virgin (non-amplified) D-104 likes to see
something higher than 100K for its load.  The amplified base has a IC
that is equal to a FET thus the input Z for the mic is near 1 meg.
(depending on feedback gain of the device)

Secondly, the D-104 crystal element is very prone to go bad due to heat
and humidity.  A new element may solve the problem and restore the
"lollypop" to good as new.  Again, high frequency response is the first
to go.

73
Bob K4TAX

Clark Savage Turner wrote:
> 
> On Sat, 12 May 2001, mike bryce wrote:
> 
> > I've always been a CW op and rarely use  SSB. When I do, I get reports of
> > "bassy' audio. I've tried D-104, Sure 444D and a handful of others.
> 
> I bet your carrier set points are not adjusted correctly.  The D-104
> should NEVER give "bassy" audio (unless you've modified it!)  Your carrier
> setpoint could be set way up the filter curve and that would cut off highs
> and only pass lows, so the mike would not have much to do with it.  The
> D-104 usually gets good reports, as does the Ten Tec mike (a few more lows
> from the Ten Tec 705).  Oh, and I think the Corsair manual may be
> incorrect in its carrier setpoint procedure, so proceed with care.  I know
> the Argosy procedure was wrong and it got carried over to another manual
> as far as I recall.  Check with Ten Tec if you want to do the adjustment.
> 
> Or, come to my shack (between LA and SF on the coast!) and try my mikes to
> see which one you like best!  Hope to see you, Mike :-)
> 
> Clark
> WA3JPG
> 
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