Just for your info, here's the article I've read... Regarding ground loops issues with wireless systems:
Another ground loop trap are wireless receivers that have a metal housing or a 3-pin power plug. Unfortunately,
within these devices, the audio ground (shield of the guitar cable) is usually connected to the chassis ex-works. The
guitar cable is therefore connected to ground in front of the amplifier, and as a result there again is the dreaded
There are several solutions for this problem:
• Professional devices have a ground lift switch, which allows you to interrupt the connection between the audio
ground and the chassis/earth. In wireless receivers, that is rather not the case. But often, a cable can just be
pinched off inside the unit, and the problem is solved. This should always be done by a trained technician. But
sometimes, the devices are designed so that a separation of audio ground and chassis inside the unit is not very
• If the receiver has a balanced output (XLR), you can apply the pseudo-symmetry trick
The Pseudo-Balanced Trick
Basically, there is nothing against having balanced wiring on a guitar rig. However, balanced connectors are offered
only in high-quality effects units, some wireless receivers and, perhaps, the one or the other modeling processor.
But with a special cable, you can connect an unbalanced connector with a balanced connector, and therefore have
a floating connection (without ground connection). This can save you a transmission transformer.
In this particular cable, the tip of the jack-plug is connected to pin 2 of the XLR connector. The ground (shield) is
connected with pin 3 of the XLR connector. Pin 1 of the XLR connector is not (!) connected.
If you connect an XLR input with such a cable, the signal loses 6 dB of its level. If you connect an
XLR output this way, the signal is boosted by 6dB. Thus, give attention to correct levels and adjust the levels using
the input and output gain controls on the device.