Multicard Audio Device Layout
- Thread starter r2d2
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If inputs of said cards are differential, you should be good. Any common-mode disturbance should be eliminated.r2d2 said:
abbey road d enfer said:
thank for post "Abbey" !
not for all ,
but for various devices this way of multicard in case of issues ( i .m.h.o.) is better for repairs ,
fast card replacement with spare cards ,
replacing damaged cards allow to use the device ,
while damaged card are fixed ,
in both of cases , live and studio situations ,
more tech opinions , helps etc.. are welcome .
cheers
For unbalanced interconnects, it takes a serious analysis of current circulations. All I can say is that star ground is far from being a panacea, because it allows different "grounds" to float and develop differential voltages, that are superimposed to the signal.r2d2 said:
Hierarchical ground is de rigueur but it's often difficult to implement in a design that has multiple inputs and outputs.
After about 40 years, you get a feeling about it...
@ Abbey...
for use less cables as possible ,
cards bridges connections can be also made with m & f connectors like molex , amp etc… ,
making the psu : V+ , V- / 0V , and gnd , enter on card n° 1 (left )
than on card 2 ,3,4 with "cascade" bridges ,
as for the audio path (obviously no out for avoid loop .. ) ,
can give some improvement ?
cheers
for use less cables as possible ,
cards bridges connections can be also made with m & f connectors like molex , amp etc… ,
making the psu : V+ , V- / 0V , and gnd , enter on card n° 1 (left )
than on card 2 ,3,4 with "cascade" bridges ,
as for the audio path (obviously no out for avoid loop .. ) ,
can give some improvement ?
cheers
I have been pretty much writing about this here for years.
Inside a common chassis there is vanishingly little benefit from balanced interfaces and cost associated with additional circuitry (while impedance balanced can be done inexpensively with just an extra resistor.)
The secret sauce, as Abby already mentioned is using differential circuits. On the input side differential circuits subtract the cold (audio 0V) from the hot to extract accurate signals. Differential circuitry can also be used at outputs to reference the signal being output to a particular output ground. This is handy inside consoles to reference an audio send to the chassis ground the output jack may be bonded to.
For differential interfaces you generally need two wires, one obviously for signal, and the second for the less obvious 0V reference. Inside a grounded chassis an additional shield is often unnecessary.
These differentials can often be incorporated into existing gain stages... for example post fader gain stages will often treat the signal going to and returning from a physical fader differentially.
This is a simplified view from 2,000 feet, but it is kind of simple when you grasp the power of differentials.
JR
Inside a common chassis there is vanishingly little benefit from balanced interfaces and cost associated with additional circuitry (while impedance balanced can be done inexpensively with just an extra resistor.)
The secret sauce, as Abby already mentioned is using differential circuits. On the input side differential circuits subtract the cold (audio 0V) from the hot to extract accurate signals. Differential circuitry can also be used at outputs to reference the signal being output to a particular output ground. This is handy inside consoles to reference an audio send to the chassis ground the output jack may be bonded to.
For differential interfaces you generally need two wires, one obviously for signal, and the second for the less obvious 0V reference. Inside a grounded chassis an additional shield is often unnecessary.
These differentials can often be incorporated into existing gain stages... for example post fader gain stages will often treat the signal going to and returning from a physical fader differentially.
This is a simplified view from 2,000 feet, but it is kind of simple when you grasp the power of differentials.
JR
> balanced interfaces ..... differential circuits
I whacked on a band-mixer, several PCBs, which was littered with the attached circuit. It derives the difference between source and destination "grounds" and allows for that in the signal path. Frequently the opamp had other function. I never heard "ground haze" in that board, though I never gave it a heavy workout.
I whacked on a band-mixer, several PCBs, which was littered with the attached circuit. It derives the difference between source and destination "grounds" and allows for that in the signal path. Frequently the opamp had other function. I never heard "ground haze" in that board, though I never gave it a heavy workout.
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