Re: Best inexpensive wireless mixer
John,
While I am an EE, I only started looking at mic preamp designs in the last couple of years in response to threads like this one 
Considering all the hoopla being made by the entire industry about "quality preamps" in various mixers, I was surprised by how simple the circuits were. Take for instance the latest hoopla being made about the X32 "MIDAS designed preamps". I have heard the argument that there is no way an X32 has MIDAS preamps, because it would cost too much.
Really?
I looked up the parts in my MixWiz, then looked up some off-the-shelf preamp IC's on DigiKey. The circuit costs almost nothing.
Even the analog circuits (all of which I found used off the shelf audio op amps) were trivial in nature.
Now to the OP's experience.
Yes, my Allen & Heath ZED 10Fx sounds better without any eq or any efx turned on than my old Behringer Eurorack UB1204. No matter how you eq the Behringer, you could always get a nicer sound from the ZED.
I am not sure that I would attribute the sound difference to the pre-amps (although that is possible), but to the entire analog chain of junk between where the XLR cable goes in, and the output goes to the amp/speaker.
In the case of the modern digital mixers, I am quite certain that you can hear the difference between them; however, the difference is not likely the pre's or even the A/D or D/A converters, but rather the quality of the processing in the digital portion of the mixer.
If you are simply amplifying the output of an iPod, any of the current wireless mixers will do the trick nicely I would think. There should be very little processing needed.
Since the DL1608 is currently the least expensive of the bunch, that would be my pick (for now ).
Now FOH speakers ...... those will make a difference on how your iPod sounds through ANY mixer
