Ummm a little something called impedance mismatch.

The output of the 77DX and the 104 are both about 0db @1 Khz
( http://www.coutant.org/3.html and
http://www.ronharter.com/astaticD104.htm )

However, the output impedance of the 77DX is low. Depending on which tap is
selected onthe onboard matching transformer .
The D104 has an extremely high impedance - on the order of 1 megohm.


You need to match 250 ohms to about 10k with a line to grid transformer.
Perhaps an Astic LT-6 or similar
(http://www.sbszoo.com/ve6sbs/sale/xform-aud.htm)





"Rich" wrote in message
news
Hi
I have a 32V-3 and it works great with the D104 non amplified
microphone. I have a RCA 77DX microphone I wired up to it and people
hear me but low?
I have the modulation knob all the way up and on the modulation meter
no movement? How can I get the microphone to modulate louder?
Thanks....Rich