Help me understand - two types of negative feedback

[5v333]

Is that network altering gain or impedance?

 

[solkatten]

No there are no actuall diffrence... Just my imagination... there were 2 diffrent plans...

 

[solkatten]

Its altering gain of the input stage...

 

[abbey road d enfer]

Is that network altering gain or impedance?

Actually it bootstraps the input impedance, which is alreaday very high. The input impedance is dominated by the Miller effect, which varies with teh amount of NFB.

 

[5v333]

Actually it bootstraps the input impedance, which is alreaday very high. The input impedance is dominated by the Miller effect, which varies with teh amount of NFB.

So no gain reduction?

 

[Winston OBoogie]

Dan, out of curiosity, what is your final schematic for that input stage? As you mentioned in PM or otherwise?

 

[5v333]

Trying to do current and voltage analysis across feedback networks but the dosent seem to light up yet.

 

[solkatten]

So no gain reduction?

Its main purpose is to vary gain

 

[5v333]

Ok kool

 

[solkatten]

Ok kool

You can look at the telefunken v72a schematics for reference

 

[abbey road d enfer]

So no gain reduction?

Of course, it's in addition to the gain reduction, and distortion reduction.