DX-60A and D-104

[w2rik]

Hi, I am new to this group and I am hoping that someone may be able to help me. I have a DX-60 that works great using a 1930's Turner U9S Dynamic (Universal Ohm) high impedance mic, but I am trying to wire up a D-104 to it. I aquired the D-104 at a hamfest recently, and it was manufactured in 1976 and yes, it is amplified. The mic will work on a Hallicrafters HT-9, but will not work on a Johnson Viking II or the DX-60A!
The base of the D-104 is a TUG 8 and I wired the white mic wire to the hot of the Amphenol connector and the black and shield to the ground. I tested the head using a scope probe on the white wire and the scope ground clip on the shield wire and I see audio when the D-104 Amp pot is close to the maxed position.
My guess is that the impedance is too low, does anyone have any idea of what I can do to the mic to make it work in the DX-60A? Will bypassing the D-104 amp fix it? If yes, how?
Tnx in advance and best 73,
Rik

[W3FJJ]

Hi, Something doesn't make sense here.. D104 should work, its not an impedance problem. Im not sure
how to solve the problem, but if you using a 2 pin amphenol connector re check to make sure its on the right
pin..
 Got to be something simple like that. Once you get it working you may want to rip out the amplifier and rebuild a
fet source follower in the base, this give d104 head high input impedance to look into and low output impedance
of source will drive anything you want...

GL  Chuck

[AF9J]

The amplified D-104, amp is more for impedance matching to low impedance inputs.  So it should work at the right potentiometer setting (assuming the impedance mismatch isn't too much).  If it still doesn't work after rechecking it, and potentiometer settings, I'd say just bypass the mic amp.  The basic D-104 mic element is high impedance.   The amp was added to deal with the lower impedance inputs of newer radios.

73,
Ellen - AF9J

[w2rik]

Thx everyone for your replys. I looked into why the mic worked on the HT-9 but not the Viking II or DX-60A. The HT-9 utilizes a spring loaded center mic connecter, the others do not. I took apart the mic connector and soldered the white wire directly to the connector on the D-104 and it worked! When I reassembled it, I added a drop of solder to the DX-60A connector as well as the D-104. This fixed the problem.

Rik
de w2rik