PLEASE RECOMMEND AN AUDIO INTERFACE.

RME Fireface UFX (http://www.rme-audio.de/en_products_fireface_ufx.php)

marvinglenn - I think you should figure out what's going on with your PC. You might have challenges with other audio interfaces otherwise.

Focusrite stuff is pretty rock solid. You might have a conflict going on. Have you been in touch with Focusrite support?

I would recommend you post this message in the Hardware section of this forum - or pick up on another thread there. Plenty of discussion about the choices in that section.

marvinglenn
I'm needing a reliable AD/DA interface.   The Focusrite 8i6 is unreliable; keeps flaking out, disconnecting from Sonar.  Have you a recommendation?

Is it possible that your Windows Power Settings are allowing Windows to disconnect your Focusrite 8i6, after a certain amount of time?  For USB-connected audio interfaces, such as yours, Windows will disconnect what it determines to be 'idle' devices after a certain time limit.  This functionality can be adjusted in your Power Plan settings, and it is recommended that folks with audio interfaces that connect via USB ports that they change default Windows behavior to make it so USB-connected devices are NOT allowed to be selectively turned off or disconnected.  (for that matter, a lot of folks completely disable all turning off of devices on PC's that run Sonar, as not every device wakes up on the right side of the bed).
 
My original answer was simply based on your initial question, and it never dawned on me until now (after reading the other responses), to suggest that you look to addressing whatever is causing you grief with the interface you already have.  Doh!  :)
 
Another place to look is to look at the type of port you are plugged into.  My Presonus AudioBox 1818 VSL interface FLIPS OUT if it is plugged into a USB 3.0 port, and some other folks have reported cases where simply moving from one USB 2 port to another USB 2 port 'fixes' issues they are having.  SOOOOO, check out making sure you are using a USB 2.0 port, and if that doesn't work then try a different USB 2.0 port (you may need to move and install the drivers again after moving to different USB ports).
 
Hopefully your issues can be addressed with your current interface, as that would be expedient and cost-effective.
 
Bob Bone
 

marvinglenn
I'm needing a reliable AD/DA interface.   The Focusrite 8i6 is unreliable; keeps flaking out, disconnecting from Sonar.  Have you a recommendation?

 
Hi Marvin,
 
Assuming the Focusrite is in proper working order, it's not the source of the problem.
Are you connecting via a USB-3 port?  Unless you're running one of the later Z series motherboards, your USB-3 ports are provided via 3rd-party add-on controllers.
This opens the door to compatibility issues (similar to using a non-TI chipset Firewire controller).  The solution is to use native (integrated into the Intel chipset) USB-2 ports.
There's absolutely no advantage to connecting a USB-2 audio interface to a USB3 port.
 
I agree with the advice that you need to figure out what's going on with the (current) system.
As great as the Fireface UFX is... connecting it to a problematic system will still result in issues.
 
Provide more details on your system... and we can provide more detailed assistance.

RME whatever.
 
Determine your pricepoint and interface (FW, MADI, USB, etc.) and get the best RME Model you can.
When you are buying an interface, above all you are buying DRIVERS! RME has rock-solid drivers. New companies who otherwise specialize in preamps, midi gear, etc. can throw features into a box, but not guarantee that they will be stable and continue development. I like Presonus as a company, but I have an audio interface from them that is in a box, as they never continued development in a Win7 world. 
 
I've used a Fireface 800 for years. Quality preamps. Relatively high end conversion. Professional low jitter clocking. Analog plus ADAT/SPDIF digital connections. Flexible software routing. Everything just works!
 
If that's more than you need, the FF400 is actually an improvement.
Babyface, UFX, etc...
 
Can't go wrong!

Hi Marvin, sorry to hear that you are having a hard time with your 8i6.  Please contact Focusrite support via this link: http://us.focusrite.com/answerbase/contact

You may not have to buy a new interface.
 
Is your interface the only one?
 
Sometimes Sonar will look for the first driver in the registry. Goto:
 
HKEY_LOCAL_MACHINE\SOFTWARE\ASIO
 
If your interface is not the first one, rename the other folders in the left pane until the one you want is first in line. Just put a z or something in front of the name already there. ie: ASIOPodXT. Rename that to ZASIOPodXT. It won't affect your other sound devices.
 
If your looking for something better. RME or Roland's Capture series.
 
Good luck!

+1 for RME. Works great for me while having problems with various other brands --- won't buy anything else any more.

RME Firface 800 has worked good for me. But I haven't had any problems with the Edirol FA-66 either.

However, if your computer is having problems a new interface may not be the answer. I just throw that out there because it would suck for you to invest in a new interface and find out your problems are not resolved. If you live in the Toledo, Ohio area you can borrow my Edirol.

Thank you Lady and Gentlemen!  Once again you all confirm my admiration and respect for helpful people!
I shall use all of your recommendations and solve the problem I'm sure!

Bristol_Jonesey
I'd start by contacting Focusrite using the link provided by Matt.

Absolutely.. the best audio interface is the one you do not need to buy.