I have read through a number of threads about the LM 3886 and the design of the PCB to mount it on. One much discussed point concerning the grounds on the PCB´s concerns the power ground and the large currents going through it and the possible problems of havoc that can be caused by this if done wrong.
Most of these designs have the same or a very similar sequence of connections on the edge opposite of where the LM3886 is mounted and which is , from left to right : negative rail , ground from psu , positive rail , then speaker out + and speaker out - , and then the input and its ground.
So forgive me if there is some error in my reasoning and explain why , but based on my long years as a tecnician and working with discreete amps mostly ,what speaks against forking the input ground trace going to the center of the caps adding the speaker out ground there ? This would change the sequence of connections as follows and would keep the high currents completely away from the rest of the PCB , along with the associated problems ? And all other grounds remain as were....
Sequence then would be from left to right : negative rail , ground from psu , speaker out minus , positive rail , then speaker out + , and then the input and its ground. As is done mostly with high power discreete amps the speaker ground then returns directly to the juntion of the filter- caps . Board size stay the same and could possibly be further optimized. I cannot judge that as I have no experience with it except of what I learned reading in all the threads.
If I am , for whatever reason , wrong please correct me Thanks Michael
Most of these designs have the same or a very similar sequence of connections on the edge opposite of where the LM3886 is mounted and which is , from left to right : negative rail , ground from psu , positive rail , then speaker out + and speaker out - , and then the input and its ground.
So forgive me if there is some error in my reasoning and explain why , but based on my long years as a tecnician and working with discreete amps mostly ,what speaks against forking the input ground trace going to the center of the caps adding the speaker out ground there ? This would change the sequence of connections as follows and would keep the high currents completely away from the rest of the PCB , along with the associated problems ? And all other grounds remain as were....
Sequence then would be from left to right : negative rail , ground from psu , speaker out minus , positive rail , then speaker out + , and then the input and its ground. As is done mostly with high power discreete amps the speaker ground then returns directly to the juntion of the filter- caps . Board size stay the same and could possibly be further optimized. I cannot judge that as I have no experience with it except of what I learned reading in all the threads.
If I am , for whatever reason , wrong please correct me Thanks Michael
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A good reference to start with, for any power amplifier.
http://hifisonix.com/wordpress/wp-content/uploads/2019/02/Ground-Loops.pdf
http://hifisonix.com/wordpress/wp-c...B-Design-Guidlines-for-Minimizing-Hum-1-1.pdf
http://hifisonix.com/wordpress/wp-content/uploads/2019/02/Ground-Loops.pdf
http://hifisonix.com/wordpress/wp-c...B-Design-Guidlines-for-Minimizing-Hum-1-1.pdf
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