On 2/15/2017 9:28 PM, mcp6453 wrote:
A friend wants to record video on a Nikon D800E DSLR while using an external audio mixer. He's going to get a
line-to-mic-level cable, which solves the level problem, but I wonder what he's supposed to do about the bias voltage on
the mic input. A lot of people just ignore it, but I blew the element out of a 635A once by doing that. What's the best
solution?
If the mixer has a transformerless output there will be a capacitor
between the guts and the output connector that will block the DC. Any
unbalanced output will have a blocking capacitor, so see if it has a
"Tape Output." And if it has an output transformer, the transformer is
robust enough to not burn out from the feeble external microphone
powering voltage. Purists will warn you that this will put a magnetic
bias on the transformer and and may cause distortion, practical
engineers will poo-poo this.
You could make a box with a blocking capacitor just in case. 50 uF
should do it. Or as small as electrolytic capacitors are these days, you
could even build one into a cable connector.
Or you could send your friend to a Nikon DSLR forum and ask if there's a
button on there somewhere that will turn the external mic power off.
I'm surprised that there was enough current to blow up a dynamic mic.
You just have just been unlucky. But given that the camera input is
single-ended (not balanced), the powering voltage is applied directly
across the microphone output rather than it being cancelled out by the
standard phantom powering scheme.
--
For a good time, call
http://mikeriversaudio.wordpress.com