& Mark V
Elektret Condenser Mike Connections by DD9ZO
Problem: You cannot connect this microphone
to the radio due to low-impedance (600 - 1200) input-terminal.
Solution: Here is a small addition-device to
connect nearly all type of elektret-condenser-microphones to the rig. You do not
need to open the FT1000MP. All you need is a resistor of 1200 Ohms, a electrolyt-condenser
of 33 microfarad with about 10V Voltage and a 8-pin-microphon-plug. If you use
small components you can put it inside the microphone-plug. It is easy to built
because the FT1000MP has a positive-voltage-pin (+ 5V) already inside his
Lets start it:
To pin 2 of the plug (+ 5V) solder a 1K2 resistor. The other end of this
resistor solder to the positive terminal of a 33 Microfarad
Electrolyte-capacitor. The negative side of this capacitor solder to pin 8
(Mike-In) of the plug. The connection between the resistor an the capacitor is
now your new hot MIKE-IN-Point feeding the positive Voltage to the
microphone-unit. Connect the electret-mike via a shielded-cable with this point
and solder the shield to pin 7 of the plug an to the negative side of the
microphone-unit. Also connect the PTT-switch to pin 6 and 5 of the plug.
To prevent of ground-loops never connect pin 5 an 7 together!
That is the whole work. You can use all types of electret-microphones, even a
amplified electred-mike like a SM2 from ICOM can be used. Cheap headsets from
the computer-industries works also with this connection.
Here on my side I am using a SM2 Desk mike and alternately a small elektret-mike
from a wireless-telephone built in a HEIL-Headset. The original HC4 Microphone
from HEIL works on a FT1000MP like Mickey-Mouse in a can due to wrong
microphone-impedance (about 3K) of the HC4.
The FT1000MP Menue-point 4.4 (TX-AUDIO-EDSP) is switched to off. I often get a
...excellent-audio... report from other stations. Even with the
...German-legal-power... from a pa-stage and the dipole-antenna only 10 meter
away from the shack, I never had RF-feedback in the mike-line.
With the monitor-function on the rig, a headphone on your ears, and a dummy load
on the output you can easily test all kinds of microphones also using the
menu-settings 4.4, 5.9, 7.7, and 8.9 to create a good audio signal for your
I am not responsible for malfunction of your equipment after doing this
modification. No warranty of function for this addition-device. Guenter DD9ZO
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