There is nothing wrong, except maybe the voltage across the capsule may be a little too high. I suspect there is about 7-8V , which is much higher than the specified 3V.across.
You may try to increase the 2k resistors of the second schemo to 4.7k, or decrease the zener voltage in the first schemo.
Since you have not described the nature of noise (Hum, buzz or hiss), it's difficult to identify teh cause.
