[ProAudio] Muncy Revisited: Pin 1 to chassis through a capacitor?

[Bob Katz]

Hi, Pro audio! Happy Holidays from Bob.

Naturally, I started a firestorm on facebook asking a question about 
grounding in a headphone amplifier I'm building.

I made a mistake by forgetting to show the connection between the 0 volt 
(transformer center tap) and chassic ground... oops, so the conversation 
went downhill and even after I revised my diagram some people were 
responding to my first diagram with the error :-(

I insisted (and still insist) that EMI/RFI interference at the audio 
input is ameliorrated in Muncy's "rule 2": by connecting pin 1 to 
chassis directly at the audio input. This is the centerpiece of Muncy's 
seminal article "Noise Susceptibility in Analog and Digital Signal 
Processing Systems"

I know this from experience as well as theory, having successfully 
installed a microphone preamplifier on the 101st floor of the World 
Trade Center in 1995 or so.

Now on Facebook, a genuine expert in power supply regulation design said 
"that will make the regulator unstable cause it sees every ground 
current as an error".

I'm not expert enough to either verify or refute the above statement, 
but perhaps my response to his statement could be to recommend 
connecting pin 1 to chassis through a capacitor.

Would the experts on this group please comment on these thoughts? Thanks.

I think that this reflector does not permit attachments, so here is a 
link to my simple block diagram, which is essentially a simplification 
of Muncy's Figure 1 in his paper if you'd like to refer to the diagram:

https://crush.digido.com/?u=pro_audio&p=muncy


Thanks in advance,


Bob




-- 

If you want good sound on your album, come to Bob Katz 407-831-0233 
DIGITAL DOMAIN MASTERING STUDIO Author: *Mastering Audio* Digital Domain 
Website <https://www.digido.com/> No trees were killed in the sending of 
this message. However a large number of electrons were terribly 
inconvenienced.
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