D104 T-UG8 Amp ICOM 701

[K4NYK]

I need to keep the 9VDC superimposed on the MIC line from the IC-701 out of the preamp in the T-UG8. The initial reccomended 'fix' is an electrolytic cap, + side to the radio, in the MIC line. I tried a junkbox 220uf (first one I grabbed) and the complaint is 'something is wrong with your mic' and 'sounds tinny'. Obviously I have created a high-pass audio situation. A reccomended value or other fix would be appreciated.
73, Louis
eMail K4NYK@schubie.com

 

[regencycb]

I need to keep the 9VDC superimposed on the MIC line from the IC-701 out of the preamp in the T-UG8. The initial reccomended 'fix' is an electrolytic cap, + side to the radio, in the MIC line. I tried a junkbox 220uf (first one I grabbed) and the complaint is 'something is wrong with your mic' and 'sounds tinny'. Obviously I have created a high-pass audio situation. A reccomended value or other fix would be appreciated.
73, Louis
eMail K4NYK@schubie.com

A 10uf should be large enough. As far as the tinny sound you have an imp mismatch. You may trying inserting a 50k Ohm 1/8 watt resistor in series with the mike audio lead and capacitor . the resistor& cap could also be placed in the base of the mike in series with the white lead this should improve the lows .

Try turning the vol control on the D104 up 1/2 way and the mike gain on the radio as low as you can to get the audio output you need.

If this does not help you may have a damaged D104 mike element.


73 RCB

 

[HiDef]

#1 guess is a bad mic head as said. Did it work OK with the internal battery?

If that's not it are you sure it's a 220 uf and not pf. I know it sounds dumb but 10 uF is plenty to pass all the low end you will need at that input impedance.

BTW, you would probably have much better tone with a different preamp.