On 05/15/2012 06:10 PM, Fons Adriaensen wrote:
Excuse my newbie question, but I'm not experienced with SPDIF.
Can one [word-clock] sync two devices using SPDIF or ADAT and still use
the analog I/O on both? -- Is that hardware specific or is there a
standard for that?
I assume the master-device will need to send a signal via SPDIF.
I'll check later if the 1818VSL can do both: output to SPDIF and analog
at the same time. but I don't know if I can do that remotely. What I do
already know is that the clock-source for each input can be configured
individually. but I'm still waiting for Brian to connect the device. my
ssh login already works..
>> What is not clear to me is
Here it mainly concerns the outputs: In my case there's a ground loop
between my Screen (Asus VE278) and the active speakers when connected
via computer and an USB UA-25 (not UA25-ex which features a ground-lift
switch) -> 1/4inch TRS -> B2031A speakers.
Disconnecting either the screen or the speakers (and using headphones)
works, otherwise there's a hum on the system; luckily no sparks, no
x-runs, either :)
A multimeter shows a constant 1mA current and ~3-4mV AC potential.
(measured between the USB-shielding of the PC and the disconnected
USB-cable of the UA25) when the screen is connected.
Both the screen as well as the speakers (and computer) are connected to
the same power-stripe and share the ground.
Fun-fact: When disconnecting the screen the potential between USB and PC
goes up to ~150mV (IFF the computer is not battery powered otherwise
it's 0) but the current drops to nil.
/me is pondering to cut the ground-wire from the screen.. but I have so
far refrained from doing that.
Anyway at some point the interface may end up on stage somewhere and
ground-lifting may be required for the inputs, too. Although in that
case I'll likely have some ground-lifting DI-boxes around.
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