Microphone plug getting worse over time

[Yousuf Khan]

I got my laptop, it has a microphone input that seems to be getting
worse and worse over time. Initially it used to work flawlessly, no
special setting needed. Then one day a few months ago it stopped working
for no apparent reason. After some troubleshooting with Gateway, it
turned out that it needed to have the "Microphone Boost" property
enabled. It was working fine without the boost before, but now all of a
sudden it needed the boost turned on. Oh well, I turned it on, and it
began working fine again. Now today, even with the boost turned on, I
can't hear anything from the microphone. I've already gone through the
procedures of trying the microphone on a different system and all, and
it works on other systems. What would be causing such a simple thing to
start degrading over time like this?

Yousuf Khan

 

[Michael Daly]

What would be causing such a simple thing to
start degrading over time like this?

Corrosion or a loose connection in the mic socket? That usually doesn't cause a
slow degradation, but will cause incremental (good connect - mediocre connect -
no connect) over time. If it's a preamp problem, I doubt it's made of discrete
components so there's not much you could do.

Mike

 

[YKhan]

slow degradation, but will cause incremental (good connect - mediocre connect -
no connect) over time. If it's a preamp problem, I doubt it's made of discrete
components so there's not much you could do.

Thanks for the reply, this time it turned out that it was the
microphone itself at fault, unlike the last time. Last time I spent a
bit of money buying new microphones to test out, and it turned out it
was an issue with the mic port. This time I didn't bother and it turned
out it was the mic now.

 

[Franc Zabkar]

Thanks for the reply, this time it turned out that it was the
microphone itself at fault, unlike the last time. Last time I spent a
bit of money buying new microphones to test out, and it turned out it
was an issue with the mic port. This time I didn't bother and it turned
out it was the mic now.

The next time you have a problem I'd connect a dummy stereo plug and
measure the voltages at the tip and ring terminals. Typically you will
see a clean +5V supply which is generated by the sound card to power
the FET amp inside a condenser/electret microphone. On some sound
cards you will see this supply voltage on both the tip and ring
terminals, on others the supply will be applied only to the ring
terminal (the tip is the signal input).

See
http://www.epanorama.net/circuits/microphone_powering.html#soundcard

Also be aware that the preamp in the sound chip is optimised for
condenser mikes. These have a much higher output than dynamic mikes.
Maybe that's why you have a "boost" option ???

BTW, your question is OT for this group.

- Franc Zabkar