I'd like to point out, since it didn't occur to me for awhile after I had it, that the front XLR inputs on the UA5 also accept 1/4" plugs down the center. Might want to try to find out if those are handled differently than the XLRs.
I needed a way to plug in my AT822 (1/4" mono, 1/8" mono, or stereo mini) into the UA5 and after some head scratching said to myself, those holes look about the right size. Sure enough, they plug in there and it looks like there is a switch inside as well that kicks when you plug in a 1/4".
One more post and the t's start flying!
I suspect they are there for instruments...guitars, keys...and perhaps that kind of unbalanced mic in...
Yep, the UA-5 front plugs that accept 1/4" can also be used w/ unbalance cables. I ran my Nak CM300's in this way until I got new mic cables. Worked just fine. The only drawback to the 1/4" unbalanced is that you cant use the phantom power, but w/ Nak's, you dont need phantom.
Also, last Thursday, I ran SBD XLR out > UA-5 XLR In, front panel > JB3. My UA-5 peak light was flickering and flashing like crazy, so I assumed I'd have a junk recording, although my JB3 levels looked fine. I had the front gain knobs turned completely "off" and still was peaking like crazy. Second set, I switched to run analog out of the UA-5 to try to control the hot signal from the SBD. When I got home and listened, turns out I could have left the setup the same as the first set. The recording came out amazing !! Like I said, the peak light was flashing like never before, but it worked out fine. That is the one and only time I ran SBD > UA-5 using XLR into the front of the UA-5. I only did it because that was the only option I had that night. Seemed to work out fine for me. Good luck, only thing I can say is give it a try and see what happens.
Jim