DC Servo, what is it

[petemoore]

   http://www.diy-central.com/DIYSC1MicPreampPCBKit.aspx
 
 Shows one here^, also shows balanced line driver and...
 anyone try this for a mic input ?
 I tried:
 http://search.yahoo.com/search?p=DC+servo+wiki&fr=chr-offrhap
 But that was all DC motor and ac motor talk.
  oh yea, was looking for something to mellow out the peizo I have in a wafer wedged under the bridge [mustache type] in my parlor guitar, plenty of signal after the Jfet buffer, but it's 'hard' sounding, gets body tone [I have a rosewood wafer the peizo is imbedded in], needs eq at the very least, thinking maybe eq compression but I want feedback reduction [so comp is kinda going the wrong way with gain when not playing].

[edvard]

From http://www.fullnet.com/~tomg/gooteesp.htm#2

DC SERVO FOR AUDIO AMPLIFIER:

This type of DC SERVO is meant to keep the DC offset voltage at the output of an amplifier at about zero volts. Typically, a DC Servo is used with an audio amplifier so that AC-coupling/DC-blocking capacitors can be omitted from the signal path.

Now we BOTH know something new...

but I want feedback reduction [so comp is kinda going the wrong way with gain when not playing].

Maybe a Limiter instead?