[LAU] 3.5mm microphone into audio interface?

David Kastrup dak at gnu.org
Sun Apr 11 15:00:49 CEST 2021

Alf Haakon Pietruszka Lund <alf at mellomrommet.no> writes:

> On 10.04.2021 19:06, David Kastrup wrote:
>> Alf Haakon Pietruszka Lund <alf at mellomrommet.no> writes:
>>> On 10.04.2021 17:15, David Kastrup wrote:
>>>> David Kastrup <dak at gnu.org> writes:
>>> Isn't it possible to switch off phantom power on the Behringer
>>> interface? On many such USB devices I've used, phantom power is an
>>> option, not 'always on'
>> Sure, but that still leaves you without plugin power.
> I see I missed a small but important point; these are condensator
> mikes. Yikes...

Yes and no: electret condenser.  They don't need phantom power for
polarising the capacitor capsule as it comes prepolarised.  But they do
need some power (typically 3V–6V) as plugin-power to power the built-in
FET preamplifier without which the weak capsule signal would not make it
through the microphone cable.

The infamous Neewer BM800 can convert phantom power to plugin power and
thus can be run on either depending on the cable type (while providing
S/N ratios that are not impressive for either application).

But a lot more typically, devices only work with one kind of power.  The
kind of soundcard/computer providing 3.5mm TRS (or TS) microphone inputs
tend to carry plugin power (sometimes switchable by software), XLR
inputs tend to have an option for phantom power (almost always +48V
these days), sometimes switchable in groups.

David Kastrup

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