I have just bought an apogee duet for my laptop. The problem is that it has a mini-firewire instead of a normal, powered bus.
Now i'm drawing the power from my charger in that way:
DA0 => DA0
DA1 => DA1
DB0 => DB0
DB1 => DB1
Inner shield => Inner shield
Outer shield => Outer
P+ => AC adapter power
PG => AC adapter ground
I belive this to be fine because the power charger ground is related to data signals by the circuitry at the guts of the laptop, but sice i plan to add an external charger for the duet to allow better mobility and also add some snake oil i will need to relate the power ground to the signal voltages.
Should the power ground be tied to the external shield at the power taking point?
Thanks
Now i'm drawing the power from my charger in that way:
DA0 => DA0
DA1 => DA1
DB0 => DB0
DB1 => DB1
Inner shield => Inner shield
Outer shield => Outer
P+ => AC adapter power
PG => AC adapter ground
I belive this to be fine because the power charger ground is related to data signals by the circuitry at the guts of the laptop, but sice i plan to add an external charger for the duet to allow better mobility and also add some snake oil i will need to relate the power ground to the signal voltages.
Should the power ground be tied to the external shield at the power taking point?
Thanks