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Scott Dorsey Scott Dorsey is offline
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Phil Allison wrote:
Scott Dorsey wrote:

4. All the GkTB equations we were forced to memorize in school are useful at
RF but not useful in a mismatched low frequency world.


** False. Johnson noise is dominant in any resistive source situation.


Resistive source? An SM-57? I think maybe this is where one of the problems
is located.
--scott


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"C'est un Nagra. C'est suisse, et tres, tres precis."
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Phil Allison[_4_] Phil Allison[_4_] is offline
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Scott Dorsey wrote:
---------------------



4. All the GkTB equations we were forced to memorize in school are useful at
RF but not useful in a mismatched low frequency world.


** False. Johnson noise is dominant in any resistive source situation.


Resistive source? An SM-57?


** Run an impedance test yourself.

From a few hundred Hz up to 15kHz, it is nearly flat.

There is a broad peak around 120Hz IIRC.

Essentially a 270 ohm source.

The internal auto-tranny just ups the value by a factor of 20 from the 13 ohms capsule.

Reason why makers use a simple resistor for pre-amp specifications.

And the type does not matter !!



.... Phil







I think maybe this is where one of the problems
is located.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."


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