[ltp] Thinkpad R40 mic input and phantom power

[Richard Neill]

Christopher Sawtell wrote:
> On Tue, 20 Dec 2005 15:44, Ben Pearre wrote:
> 
>>I know, I should call IBM or Intel, but I like you guys better :)
>>
>>Any idea whether the R40's soundcard supplies "phantom power" to the
>>microphone jack?
> 

It's certainly true for the A22p, since I use an electret microphone
with it. But if you are worried, put a capacitor of perhaps 0.1uf in
series with your Mic: this will block the phantom power. That said,
iirc, the only mics that don't use phantom power are

i)crystal piezo mics (very cheap/indestructable)

ii)moving coil mics - which shouldn't care if you pass a small current
through them.


Richard