I am glad you found my post useful, the way you describe it is exactly what I hear. Noise and interference every time the poly communicates via wifi. You hear it when glider syncs, I can hear it even when scrolling through my dlna library (as I am sure it refreshes and updates dynamically as I scroll). Switching to the jack definitely helped, in some cases. And just like you, the better jack is the one closer to the LED control balls on the mojo.
However, I should also note that if you read on further as I continued that initial discussion,
@Matt Bartlett and
@Mojo ideas both let me know after I posted that, that there should be no difference between the two mojo jacks in terms of shielding. However, the difference I heard was real. I should also mention though that the improvement I heard was only in certain situations. At home, sitting at my desk, it worked ok in that jack (still bad in the other), but doing the same thing at work yielded no improvements at all from the different jacks. In that case I dont know if its because the wireless interference at work is greater, or because I use my phones hotspot and not a separate wifi network, or what. But switching the jack made no difference there, so it is unfortunately a solution that only seems to work some of the time and in some specific circumstance that I am unsure what it is.
It is a real shame because the mojo sounds excellent otherwise, and the poly is a very nice addon, even with all the growing pains and difficulties getting it to where it is now (and there is still more than needs to be done). But, the interference is really really frustrating and extremely disappointing that it is so noticeable on a product that costs combined about $1200 dollars in the US. And worse is that it seems like there is nothing actually wrong with my units, its just that with sensitive IEMs, it picks up interference. Doubly frustrating too is that the interference is known on the mojo, yet it was supposed to be from using USB. The poly was supposed to eliminate that, but seems to have had no effect or possibly introduced even more intereference, at least for me when using my headphones of choice. I should also note again that using it with something like my Senn HD6XX, and I cant hear the interference at all.
But the whole point of getting these units for me was for portable use, for use with my IEMs. All I have for comparison is a little rinky dink $100 dollar earstudio ES100. Sure it doesnt have wifi, but it uses bluetooth and is dead silent. And the interference unfortunately gets under my skin enough (among some of the other issues, like the poly battery dies after a couple weeks even when powered off) that I barely ever use my mojo/poly.
