D-104 Mic

[DDWEBB]

I have been reading about the  different microphones used by fellow K2 owners.
A fellow ham encouraged me to  try a vantage, (1960s) D-104 crystal mic for
the K2. I had been using a Kenwood  MC-48B and it was working OK. I knew that
the straight D-104 mic would not work  with the K2 as crystal mics are hi Z and
the modern solid state Mic inputs are  low Z. One model of D-104 however has
an amp in it's base and it works fine. I  get better signals quality report
with the D-104 then my previous mic. I don't  mind that the mic towers almost a
foot over my K2 as I have big hands  anyway.
Just another Idea.

Don...KA7L  

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[roncasa]

heh heh
I loved your line ... "towers almost a foot over my K2"

man, the mike is bigger than the radio!
I can visualize a ham wrestling with a giant mike connected to a
teeny radio ...
That brought smiles to my face, thank you.

Ron, wb1hga
"Elmer the inquisitive"

[hidden email] wrote:
> I have been reading about the  different microphones used by fellow K2 owners.
> A fellow ham encouraged me to  try a vantage, (1960s) D-104 crystal mic for
> the K2. I had been using a Kenwood  MC-48B and it was working OK. I knew that
> the straight D-104 mic would not work  with the K2 as crystal mics are hi Z and
> the modern solid state Mic inputs are  low Z. One model of D-104 however has
> an amp in it's base and it works fine. I  get better signals quality report
> with the D-104 then my previous mic. I don't  mind that the mic towers almost a
> foot over my K2 as I have big hands  anyway.
> Just another Idea.

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[Ron D'Eau Claire-2]

Unlike almost all modern mics, the original D-104 has a shaped frequency
response curve for optimum speech quality. It has a broad peak in the 3 kHz
range to pick up the sibilance essential for intelligibility, with good
roll-off characteristics at the higher and lower frequencies.

Since filter SSB rigs (like the K2) became the norm, I've noticed that more
and more "communications mics" are simply the same old "hi-fi" elements
packaged for Ham use. They depend upon the filter characteristics of the rig
to limit the high and low frequency response, and generally do not provide
any rising characteristic in the 3 kHz range that can produce the clear,
bright audio that helps intelligibility, especially when copying a signal
under rough conditions.

Remember that when the D-104 came out, rigs didn't have filters! The speech
was shaped slightly by choosing the right combinations of resistors and
capacitors in the "speech amplifier" but generally any frequency between a
few Hz and 10kHz (or more) that came into the mic went out the antenna, so a
mic with proper shaping was an essential element of any good 'phone station
back then.

It's a great mic and a real icon. If yours has the original element, it may
well be a Rochelle salts crystal element. Of so you're fortunate it's
survived. They are easily destroyed by physical shock (knocking the mic over
or dropping it) and temperature extremes. If you open the "lollipop" top,
you'll see the element suspended in rubber inside the ring to help protect
it from shock. The Rochelle salts crystal is also water soluble. If exposed
to high humidity for any length of time, they dissolve! The element was
hermetically sealed when it was made, but it seems that some of the seals
fail over time (or curious fingers broke them).

Rochelle salts elements were replaced by ceramic elements in most
microphones at some point in the late 50's and 60's , but I don't know if
Astatic ever went to a ceramic element for the D-104. Ceramic elements are
lot more stable and strong, but not virtually indestructible like most
modern dynamic and electret mics! Without specific data, I'd assume it's a
Rochelle salts crystal and treat it like "royalty". After all, among mics,
the D-104 definitely qualifies.

Ron AC7AC
 

-----Original Message-----

I have been reading about the  different microphones used by fellow K2
owners. A fellow ham encouraged me to  try a vantage, (1960s) D-104 crystal
mic for
the K2. I had been using a Kenwood  MC-48B and it was working OK. I knew
that
the straight D-104 mic would not work  with the K2 as crystal mics are hi Z
and
the modern solid state Mic inputs are  low Z. One model of D-104 however has

an amp in it's base and it works fine. I  get better signals quality report
with the D-104 then my previous mic. I don't  mind that the mic towers
almost a
foot over my K2 as I have big hands  anyway.
Just another Idea.

Don...KA7L  

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[Don Wilhelm-3]

Don,

There was a report somewhere within the past few months that one ham
successfully used his unamplified D-104 with a low impedance rig (it may
have been a K2).  He simply added a series resistor to keep the mic looking
into a high impedance and it worked fine.  I have not tried it here, but I
would recommend that you use a series resistor value greater than 470k ohms.
The D-104 element has plenty of output voltage.

The amplified D-104s work just fine with low mic input impedance
transceivers.

You could search the reflector archives in case it was on this reflector (I
do think it was, but my memory is fuzzy).

Don W3FPR

> -----Original Message-----
>
>
> I have been reading about the  different microphones used by
> fellow K2 owners.
> A fellow ham encouraged me to  try a vantage, (1960s) D-104
> crystal mic for
> the K2. I had been using a Kenwood  MC-48B and it was working OK.
> I knew that
> the straight D-104 mic would not work  with the K2 as crystal
> mics are hi Z and
> the modern solid state Mic inputs are  low Z. One model of D-104
> however has
> an amp in it's base and it works fine. I  get better signals
> quality report
> with the D-104 then my previous mic. I don't  mind that the mic
> towers almost a
> foot over my K2 as I have big hands  anyway.
> Just another Idea.
>
> Don...KA7L
>

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[Bob Nielsen]

On Feb 23, 2007, at 2:03 PM, Ron D'Eau Claire wrote:

>
> It's a great mic and a real icon. If yours has the original  
> element, it may
> well be a Rochelle salts crystal element. Of so you're fortunate it's
> survived. They are easily destroyed by physical shock (knocking the  
> mic over
> or dropping it) and temperature extremes. If you open the  
> "lollipop" top,
> you'll see the element suspended in rubber inside the ring to help  
> protect
> it from shock. The Rochelle salts crystal is also water soluble. If  
> exposed
> to high humidity for any length of time, they dissolve! The element  
> was
> hermetically sealed when it was made, but it seems that some of the  
> seals
> fail over time (or curious fingers broke them).
>

I dropped my D-104 several months after I bought it (around 50 years  
ago) and know well what you mean.  I mailed the head to Astatic  
asking them to replace the element and let me know how much it would  
cost.  The repaired mike was sent back to me a week later--no  
charge!  I still have it and wonder what shape the element is in.  I  
may throw together a transistor amp and give it a try with my K2 one  
of these days.

Bob, N7XY


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[Ron D'Eau Claire-2]

Ouch!! That's a great story though. I got similar personal support from the
National company back in the 60's. Elecraft's excellent customer support
isn't something new; it's just something that's been missing from too many
companies for too many years.  

You might try the suggestion Don Wilhelm made: put a large (appx 470k ohm)
resistor in series with the hot side of the mic and drive the K2 directly
with it. He's heard that it still has enough gain to work that way.

Of course, the large resistor is essential to preserve the frequency
response characteristic: that is affected by the load impedance on the
output.

Ron AC7AC

-----Original Message-----
I dropped my D-104 several months after I bought it (around 50 years  
ago) and know well what you mean.  I mailed the head to Astatic  
asking them to replace the element and let me know how much it would  
cost.  The repaired mike was sent back to me a week later--no  
charge!  I still have it and wonder what shape the element is in.  I  
may throw together a transistor amp and give it a try with my K2 one  
of these days.

Bob, N7XY


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[Bill Steffey NY9H]

At 04:03 PM 2/23/2007, Ron D'Eau Claire wrote:
>Unlike almost all modern mics, the original D-104 has a shaped frequency
>response curve for optimum speech quality. It has a broad peak in the 3 kHz
not unlike all modern mics,,,,,

the Shure  SM58...  is probably the world's most popular mic model...
which has/had been the standard of the rocknroll industry since Heil was a pup.

"""The SM58 has a tailored vocal response for a sound which is a
world standard.

Rugged construction, a proven shock mount system, a....speech - the
SM58 is the overwhelming choice of professionals.

The legendary Shure vocal mic is tuned to accentuate the warmth and
clarity of lead and back-up vocals. Consistently the first choice of
performers around the globe...
;;;;;;it's up 5 db at 4khz...

bill

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