When using a DPA miniature lapel mic with the UR1 transmitter, I noticed some low level background noise. This noise was not there with my Shure lapel mics. Any ideas?
The DPA lapel mic cable likely was wired with a microdot connector. DPA sells a microdot-to-TA4F adapter called the DAD6010. If you use that adapter, make certain the adapter's outer case/shell is connected to pin 1. (The mic cable shield is also connected to pin 1.)
If you replaced the microdot connector with a TA4F, make certain the TA4F outer case/shell is connected to pin 1.