Class D amplifiers have very little phase shift


Too many diagrams to post here, so I just blogged it:

https://inatinear.blogspot.com/2020/02/class-d-amplifiers-do-not-have-horrible.html

The 20 degrees at 2 kHz argument is bunk.
erik_squires
It may help to think of where the test probes are. For the first chart, the probes are:

Amplifier --> (+) Output Impedance (-) --> Speaker

For the second:

Amplifier --> Output Impedance  --> (+) Speaker (-)




Yes, yes, I am a new here and only ever read these forums usually for a laugh, and have posted this time because I feel the need to.

 I'll post this once just for the ignorance of those that believe all Class-D have the next to no phase shift from the upper/mid right up to the highs. It has been quoted to look at graphs of x Class-D as it "only" has x phase shift and they used this to compare it to other Class-D modules. Some even being cheap subwoofer modules used.

It's false,  and those here who “consider themselves” to be EE’s should know better, you know who you are and should lay low to giving your tick of approval to this garbage.

 Because some of these comparison modules are measured with/without their output filters insitu, and the manufacturer has used Audio Precision "very high order" external “test filtering” instead for the graphs, and/or the frequency knee of the output filter they use if used, is totally different to the one it's being compared to by the one doing the comparing, which will directly effect the amount of phase shift down lower in the audio band as those of us all know.

This thread is just plain bunkum.
That helps,  it's where I thought they were measuring and that's  why the first graph was misleading they put the probes on the PCB. Not sure what jesskerry is on about I don't  consider myself to be anything other than trying to understand. 
@djones51

I don’t think the graph itself is misleading. It’s that is’ so very very rare. I have seen output impedance plots, rarely, but never one with phase also.

It’s truly something for the geeks.

Best,

E