I personally don't recommend buss power if you can avoid it. 
I have read a lot of threads here where people have issues like hum and not enugh power for phantom mikes etc. I have a friend who bought a Scarlett 2i2 who had a heck of a time with his laptop and hum. Then one of his LDC mikes will not work at all with it. 
And if your needing multi channel recording / playback that will narrow the choices down to a couple of interfaces? That's not really a way to purchase something as important as a interface.  Like how inconvenient is it to plug in? Are you busking? 
After all , any multi channel recording will be done where there is power available so why bus power? USB was not designed to supply power so it is a compromise only for convenience and is well known to cause issues on some systems.  
 

johnnyV
I personally don't recommend buss power if you can avoid it. 
I have read a lot of threads here where people have issues like hum and not enugh power for phantom mikes etc. I have a friend who bought a Scarlett 2i2 who had a heck of a time with his laptop and hum. Then one of his LDC mikes will not work at all with it. 
And if your needing multi channel recording / playback that will narrow the choices down to a couple of interfaces? That's not really a way to purchase something as important as a interface.  Like how inconvenient is it to plug in? Are you busking? 
After all , any multi channel recording will be done where there is power available so why bus power? USB was not designed to supply power so it is a compromise only for convenience and is well known to cause issues on some systems.  
 

USB was not designed to supply power? Are you serious?
 
All these recommendations are pretty funny I must say! First of all, "Johnny V", I have plenty of other stuff (MOTU 2408MK3, Motu 1224, Plenty of rack-mounted preamps, VS100 etc etc) so all your statements are not just beside the point, they're completely irrelevant. Who said anything about phantom power?
 
The point is I'm NOT going to be recording with this, it's for doing gigs, running tracks! I need to be able to send stereo tracks to the house, click and mono track to the drummer, and hopefully separate BU vox to the house as well.
 
R

According to Thomann, there is only one USB bus powered interface with 6 analog outputs: Fast Track C-600.
Unfortunately,  only 4 outputs are available in USB bus powered mode.
 
So, it looks like that such interface is not yet invented...

azslow3
According to Thomann, there is only one USB bus powered interface with 6 analog outputs: Fast Track C-600.
Unfortunately,  only 4 outputs are available in USB bus powered mode.
 
So, it looks like that such interface is not yet invented...

Finally a response from someone who read the question!
 
I was afraid of that answer! Hoping someone will step up to the plate and make such a beast.
 
Thanks!
R

Good luck finding something. My RME Babyface has 12 out, but 8 are ADAT and it runs only on USB. So I doubt if you find one that has 6-8 analog out (not ADAT) without connecting to some kind of walwart power supply.
But then since the UCX is 9-18 Volts (which is DC) (12 watts) center pin probably can run off of a 12V battery, but then I am not using any that way, so that is all I can say, I do not intend to run one that way. And I would not recommend anyone run one that way without checking it all out first.
 
But I guess you have your choice of one, so is posted it seems to be that way.
USB only puts out 500 milliamps so that includes anything else ran off of the same port (USB Hub) also.
Not much power to run anything, and then there is the bandwidth that the USB port can handle also.
Not any camera I know of that can download into a computer probably don't have a power supply also that needs to be plugged in (like a line power cord), although they will run off of a battery you can buy for the camera for power also I suppose which does happen for a limited amount of time. (I use my old cam-corder that way, but the battery needs to be recharged by a AC power line cord plugged into power after running down.) (and they include a USB connection but I doubt the cam-corder runs only on that - I do not know).
??
If a RME unit could run off of a battery (like a camcorder) then I do not know what could be bought. You would have to ask RME about that.
http://www.rme-audio.de/forum/
 
Telescopes run off of a battery (usually a car battery or motocycle 12V battery) or AC line power.
 
 This post sort of makes sense to me, whether it does to you - well the post was edited.
 
The UCX would take 12 watts of power to run it. It is not going to run off of a USB port, but maybe a battery, but then I do not know what kind of battery it could use if any, also like the UFX. (and I doubt if anyone uses any audio/interface that way. Again I do not know).
Otherwise I guess anyone does not make it, except for that one mentioned in the previous post, but I be leery about that one claiming that.
 
 

eikelbijter
......
All these recommendations are pretty funny I must say! First of all, "Johnny V", I have plenty of other stuff (MOTU 2408MK3, Motu 1224, Plenty of rack-mounted preamps, VS100 etc etc) so all your statements are not just beside the point, they're completely irrelevant. Who said anything about phantom power?
 
The point is I'm NOT going to be recording with this, it's for doing gigs, running tracks! I need to be able to send stereo tracks to the house, click and mono track to the drummer, and hopefully separate BU vox to the house as well.
 
R

Wow! Sorry I tried to help...
 

Car cable or battery cable for power supply for RME.
http://www.rme-audio.de/en_products_cables.php
 
run off of a 12V battery, the other listed is  a walwart cable power supply connection and AC power line cable.
 

I know exactly what you were asking about. 
You don't have to come back at me like that? what up with that? 
 
I'm just trying to point out why what your looking for will be so hard to find. 
There's a limit to what can be powered with usb 2.0. So I'm not kidding at all. 
 
USB 3.0 has more power available. But go ahead and find a USB 3.0 interface. 
 

I missed the USB-powered part of your initial post because quite honestly it didn't register when I read it, as nobody's gear works that way.  
 
I apologized earlier for my missing that, fair enough.
 
Bob Bone
 

As you're wanting to use it to feed tracks to a PA, why don't you just get a mains power feed from the PA guy/girl to power a normal interface?
 
Or is the PA working from USB bus power as well?
 
You want to send a click track to your drummer, so presumably there are instrument amps on stage for the drummer to hide behind.  Are these USB powered as well?
 
 
I'm a FOH sound engineer, it's part of the job to supply power.  You'd be better off spending your time looking for a mains extension lead rather than a USB powered interface which would run down the battery in your laptop so you'd need power for that anyway....