modifying HDAM betters phasemargin

[crimson_tobi]

I've searched the forums to find something about this topic... No success...
If somebody already wrote about it (I guess not!), I will repeat.


The simulation of the marantz CD63SE HDAM shows that the circuit suffers from low phasemargin.
As it is used as a buffer (its gain is unity) the phasemargin is around 45°. Transit frequency is around 10MHz!
The internal compensation network (33k and 47p) would only work for much higher gain.
Changing the 33k to 220R pushes the network to the 10MHz region.
Simulations show that phasemargin rises up to 65°.

What's it good for?
Lower overshoot at MHz region.
Much better pulse response.

Is it audible?
Don't ask me, because I also cleaned up Servo and u-Proz supplies and did some filtering in some other place at the same session.
But I guess it is!