[sdiy] Electret microphone experiments, the sequel

[Razvan Tataroiu]

hi
I think you need 2 batteries to operate the opamps. Try tying the VCC-
of the opamps to the - of another battery, whose + is tied to the GND
in the schematic. If you get this to work, you might then use a single
battery, but you'll have to "create" a GND at half the battery voltage
(with another opamp)

On 8/26/05, Bert Schiettecatte <bert at percussa.com> wrote:
> Hi All (again),
> 
> I tried to build a 'high performance' electret microphone amplifier
> circuit this morning:
> 
> http://www.eclectic-web.co.uk/index.php?jump=http://www.eclectic-web.co.
> uk/mike/electret_a.htm
> 
> I used three LM833D's since I don't have a lot of opamps around. I
> connected the VCC+ of the LM833's to the + of the battery and the VCC-
> to the GND point near the two 10nF caps in the middle of the schematic.
> I installed a 10K trimpot instead of the 100 ohm resistor.
> 
> It doesn't seem to work, I get nothing on my scope or maybe very very
> little signal. I tried replacing the trimpot with a 100 ohm resistor
> because I thought maybe the trimpot was broken. No result.
> 
> Can anyone shed some light on what I'm missing here? I'm probably asking
> very basic and silly questions here, but I come from a CS background and
> still learning a lot about electronics...
> 
> Thanks !
> 
> Bert
> 
>