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Phil Allison[_4_] Phil Allison[_4_] is offline
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Default Mic preamp build?

Scott Dorsey wrote:

What are your thoughts on this?
http://sound.whsites.net/project66.htm




This circuit is pretty much what you will find in any transformerless mike
preamp with a couple exceptions.. everything from Millennia to Mackie. It is
as good as the front end is allowed to be.

The 2N4403 is not exactly a low noise transistor but if you're careful about
where you get them and cull out the occasional outlier, they can work pretty
well in this circuit.


** The 2n4403 is still one of the best available devices for low noise at microphone impedances. The measured noise figure of 1dB speaks for itself.


I disagree strongly about there being no problem with DC bias on modern
electrolytics,


** Disagree all you like, but there is no issue.


I might
also dramatically increase the values of C2 and C3 well beyond the values
needed to get good response.



** Using 10uF caps as shown gives a -3dB point under 1Hz.


..... Phil