I have encountered a strange issue. I own QLX-D and ULX-D. Both sound great on guitar. But on some guitar setups, I've noticed that there is an odd audible noise present. Any ideas?
Some guitars (and other instruments) with poorly shielded or poorly grounded internal preamps / electronics can be susceptible to noise into the audio path if used with ULXD and QLXD. This is caused by a radio frequency component present in common digital transmission schemes, such as used in QLX-D and ULX-D.
Sometimes the noise can be reduced by moving the wireless transmitter farther away from the guitar body. The better solution is to improve the shielding / grounding in the guitar electronics if possible.