I have some questions again. 2 cards, noise leak

Stige · Post by **Stige** » Fri Dec 19, 2003 10:29 am

I just added pulsar XTC side by side with Pulsar II z-link. So I'm a bit green with these multicard things.
Now i have noticed that with empty project, the DSP-load window shows around 20% load in most of the 12 available DSP's. I wonder, is this normal?
Apart from that it seems to give me the full power of 12 DSP's, and i'm able to get 15 masterverbs before it refuses to load them due to PCI capasity limit.

Is it ok to set my pulsar z-link as a first card (in cset.ini)? Or must it be as default and then XTC-card would be the first one. If z-link is the firt card, there seems to be less DSP load.

Anyone noticed this: when playing back thru pulsar's analog out, there seems to be lots of action in analog input (if they are not connected to physical devices). With level meter, i see right input channel jumping up to -60dB when playing music thru analog out. If i record that signal from analog input and listen to it, the signal of analog out can be heard there.
Is there any explanation for this? A crosstalk problem? This doesn't sound too professional to me.

Thanks for replies

astroman · Post by **astroman** » Fri Dec 19, 2003 1:02 pm

the sequence of cards is right, it is suggested that the card with the IO has priority.
For the crosstalk thing: is the STDM cable properly seated and both cards sit firm in their slots with good connection to the metal of the case ?
Does the crosstalk appear without anything connected to analog out ?

Could there be any ground loops in the external gear ?

cheers, tom

Stige · Post by **Stige** » Fri Dec 19, 2003 3:12 pm

Thanks for reply, Tom

If the analog out is not connected inside SFP, or the signal is muted in SFP mixer, there is no crosstalk at all. Or, if the analog input is connected to a outboard physical device with powers on, there is no cosstalk either. To me this crosstalk seems to be happening inside the pulsars extension cable or in the card itself, but after AD/DA conversion. I noticed, it went worse after adding second pulsar card.
Only a signal that is passing thru pulsar's own D/A converter will cause crosstalk to analog in.

STDM cables should be as properly seated as possible (i cleaned the connectors too). But they feel very loose, so i wonder if they are getting a proper contact. I have no idea how the make the connectors tighter..
Also, there is a red wire on the left side of the STDM cable. Does it matter which way i connect them? Now i have them connected so, that the red wire is pointing towards pci slot holes at the back of pc. I hope this will make any sense.

astroman · Post by **astroman** » Fri Dec 19, 2003 8:50 pm

On 2003-12-19 15:12, Stige wrote:
Or, if the analog input is connected to a outboard physical device with powers on, there is no cosstalk either.

So if the input is closed (and obviously grounded) then it doesn't matter what's connected to the output ?
It's not necessarily the cable, though that's very likely as you describe the problem.
It could also mean that a certain part of the card isn't grounded properly and the cable from outboard gear now provides the missing ground.
At least you could cure it (temporarily) by leaving something plugged in

cheers, Tom