Dan Dugan wrote:
> Good tutorial on self-noise, Walt,
I've noticed a tendency in some discussions to make the leap from the
mic spec directly to environmental noise levels without considering
gain. I may have even contributed to that in the way I've said things.
Figured it might be a good idea to correct that.
> A mike preamp with its input unterminated is usually noisier,
> sometimes a lot noisier. A more realistic test for preamp noise is to
> wire up a male xlr with a 150 ohm resistor between pins 2 and 3 to
> use as a dummy mike. I'm not sure what to do with an unbalanced
> plug-in-power input.
I would think a unbalanced input could be handled the same, plug in
power is so small it would not be a problem. Though you might want to
match the resistor to the impedance of the mic you are interested in.
The resistor would go from Signal hot to Signal cold in any case. For a
stereo miniplug input I guess you'd want to use two resistors so both
channels are loaded. Probably the same on most XLR balanced
recorders/pre's that have two channels.
Walt
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