[Boatanchors] WTB/WTT - High-Z PTT Desk Mike for HF SSB Rig

[Gary Peterson]

An unmodified, unamplified D-104 has too much output and greatly boosted high frequency response for most older SSB rigs.
This requires the audio gain control to be set, barely above 8 o clock, making it difficult to adjust.  The D-104 was designed to drive a tube grid with a one megohm resistor as a load.  When connected to a much lower impedance, the D-104 has a rather shrill bump from 1.5 kHz and beyond.

Back when I ran a Kenwood TS-820S, I solved both problems.  I placed about a 700 or 800 kilohm, metal film resistor in series with the hot lead of the crystal cartridge.  I did this inside the push to talk base.

The resistor dropped the output sufficiently such that the mic gain control could be properly set to about 10 or 11 o clock.  The series resistor increased the load impedance on the cartridge and smoothed out the frequency response.

After the above mentioned modification, it was not unusual for other operators to ask me what radio and microphone I was using because they thought my audio sounded great.  

Do not discount the venerable D-104.  As always, your mileage may vary.

Gary
KzeroCX  

“I have a couple of older tube-type SSB rigs, and I'm looking for a 
decent High-Z PTT desk mike.? I have a couple of Astatic D-104 mikes 
with the grip-to-talk stands, but I don't care for the D-104 sound on SSB.”
...
”If you have something that's surplus to your needs, I'd like to hear 
from you.? I'm willing to trade a D-104 or two if you have something I want.

Please let me know what you have (make & model).? A pic would be nice.

Thanks!

Mike Harmon, WB0LDJ”