Connecting the power adaptor is definitely worth a try. And it has to be said that firewire under Windows has been an increasingly hit and miss thing for several versions now.

As for the noise, what sort of noise is it? White noise, hum, whine....? If you record an audio track in Sonar from an interface input with nothing connected to it does the noise get recorded or is it only on the output side of the inteface?

For the price range you're talking, check out the Tascam US-16x08.  You may not need that many INs/OUTs, but the mix of IN types is very handy.
 
 

tlw
Connecting the power adaptor is definitely worth a try. And it has to be said that firewire under Windows has been an increasingly hit and miss thing for several versions now.

As for the noise, what sort of noise is it? White noise, hum, whine....? If you record an audio track in Sonar from an interface input with nothing connected to it does the noise get recorded or is it only on the output side of the inteface?

I'll have to try a recording to see what happens. The noise is a constant hum, definitely like a ground loop, but there is also an intermittent component that is cutting in an out. That noise is higher frequency and irregular. Not constant, but it pops in and out a couple of times every second, on average. It's an odd sound. It's almost like that sound that cheap PC speakers make when they're picking up cell phone signals, but not quite, and it doesn't get better when my phones are out of the room.

tlw
Connecting the power adaptor is definitely worth a try. And it has to be said that firewire under Windows has been an increasingly hit and miss thing for several versions now.

As for the noise, what sort of noise is it? White noise, hum, whine....? If you record an audio track in Sonar from an interface input with nothing connected to it does the noise get recorded or is it only on the output side of the inteface?

I'll have to try a recording to see what happens. The noise is a constant hum, definitely like a ground loop, but there is also an intermittent component that is cutting in an out. That noise is higher frequency and irregular. Not constant, but it pops in and out a couple of times every second, on average. It's an odd sound. It's almost like that sound that cheap PC speakers make when they're picking up cell phone signals, but not quite, and it doesn't get better when my phones are out of the room.

Okay, so I just did a quick test. I disconnected the firewire connector and plugging in the DC adapter to provide power. With the unit on and connected to my monitors, there was no noise at all. The noise didn't start until I connected the box to my PC with the Firewire cable. Not sure what that means, other than perhaps to dump this firewire solution and go out and buy something with USB.  

Hello,
 
Queston... Does the noise persist if you take out the firewire cable (Not when the OS is up). Have you tried a different set of monitors (sorry if you have been asked that). Lastly, Do you know which chipset is used onboard? Thanks.

The noise did not persist with the FireWire cable disconnected when using the DC power adapter, so the noise appears to be something related to the connection to the PC. I have no idea what chipset is on that motherboard. It's a Gigabyte 990FXA-UD3 mobo. I'll have to look up the details.
 
EDIT: According to the website, it uses the VIA VT6308 chip for FireWire.

Not familiar with that particular chipset, but I know by reputation that many VIA chipsets are problematic for fw audio devices.  TI chipsets are the preference usually.
 Obviously the best thing to do would be salvage your old interface, but that's not looking good.
I didn't see whether your PC is a desktop or laptop, but if it's possible you could install a PCI firewire card with a TI chipset. That has worked for many.
 
If that's not possible, I have a couple of other suggestions:
Have someone test the interface on another computer. If it's fully functional, sell it and pick up something else.
Re the Focusrite Scarlett usb interfaces: I recently got an 18i20 and am very pleased with it. Sounds great, runs great, etc.  You don't have to touch the Mix Control software if you don't want to except to adjust latency settings.
It is for setting up monitoring for headphone mixes and such.  The included plug-ins are ok and useful, but all of the things they do are well covered with Cakewalk included plugs.  The one standout is the Red Compressor.

neiby : Install cpu-z....I want motherboard make and model....and the board's current bios rev......your Os 8.0 ..8.1 ? .. whats the make and model of your video card.. I will look back later..
 
VIA VT6308 chip for FireWire is more than likely a issue... Nec chipset is standard !

Hello,
 
Hmm.. The reason I asked was that I had two issues that drove me nuts... One.. was a output from an onboard card to my interface. Took me a while to track it down kind of like power hum combined with intermitent bursts of hi frequency hash.  Took it to a engineer friend of mine who identified it as digital noise from my pc more than likely the board. In that case the output from the card I sent through an ART DTI. 
 
The other case was similar but came from usb.  When using my drum controller via usb and while having the audio output going to the interface, the same kind of noise reared again. The fix was the same also to add the noise added to the transformer hum from a secondary set of powered monitors. Between doing this (Below) and using the Art it took care of thatThus my question about trying a different set of speakers. IHTH...
 

Digital Distortion

Digital distortion is noise accompanied by "grinding" or "buzzing" sounds that appear completely unnatural. Often, they follow the processes of the computer being used; for instance, if one opens a program on their system, this noise may alter along with this process. 

Solution:

Digital distortion is usually either caused by an issue with the audio interface, or the monitors being connected to the same power strip/socket as the computer. Make sure your monitors/playback solutions are connected to a separate power source than your computer and other digital hardware. Or, make sure you are using a quality power conditioner.  Check with the support for your particular interface for more information on possible driver issues, fixes, and optimizations.