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I think there a descriptions in that thread and others about hierarchical grounding structures and how to look at grounds correctly. I also think the experts did agree that it gets harder to apply these insights in something as complex as a large format console. Me, I'm not one of the experts, I only try to apply their knowledge and wisdom.That said, when I added dirt grounds, like in the GSSL, I used thick copper wire underneath the PCB that connect to the decoupling caps as a net seperate from the audio ground, only joining the grounds at a point near the regulator ground. It might also be good practice to couple audio ground and dirt ground together at points far away from the place where the grounds actually join with a small cap, I think John explains the rationale for it somewhere in the grounding thread.My most important takeaway was Ricardo's advice to use "bad" high ESR electrolytics for decoupling to counter trace inductance and prevent resonances in the PSU impedance response.My console has no seperate "dirt" grounds. There's an external linear PSU supplying DC, which then gets dropped a few volts by linear regulators on every channel/module. All the grounds go to the bottom of each module and are connected by a steel bar on every module and jointly go to the bus bar, which is made of lot's of copper. There is no problem with hum in this console. Also not very much PSU decoupling in general. The 10uf high ESR electrolytic I added to the positive rail a the op amp in question went to a ground nearby, and I saw no negative effects from it (no visible hum/noise increase). It certainly fixed the stability problem.
I think there a descriptions in that thread and others about hierarchical grounding structures and how to look at grounds correctly. I also think the experts did agree that it gets harder to apply these insights in something as complex as a large format console. Me, I'm not one of the experts, I only try to apply their knowledge and wisdom.
That said, when I added dirt grounds, like in the GSSL, I used thick copper wire underneath the PCB that connect to the decoupling caps as a net seperate from the audio ground, only joining the grounds at a point near the regulator ground. It might also be good practice to couple audio ground and dirt ground together at points far away from the place where the grounds actually join with a small cap, I think John explains the rationale for it somewhere in the grounding thread.
My most important takeaway was Ricardo's advice to use "bad" high ESR electrolytics for decoupling to counter trace inductance and prevent resonances in the PSU impedance response.
My console has no seperate "dirt" grounds. There's an external linear PSU supplying DC, which then gets dropped a few volts by linear regulators on every channel/module. All the grounds go to the bottom of each module and are connected by a steel bar on every module and jointly go to the bus bar, which is made of lot's of copper. There is no problem with hum in this console. Also not very much PSU decoupling in general. The 10uf high ESR electrolytic I added to the positive rail a the op amp in question went to a ground nearby, and I saw no negative effects from it (no visible hum/noise increase). It certainly fixed the stability problem.
