I got a Mackie SRM150 for stage monitoring but I'm having problems getting a good connection in the hybrid-XLR jacks on the front with a 1/4 inch jack guitar cable. Even when it feels like it's firmly placed, I'll still get periodic thumps through the speaker.
Anybody have any suggestions? I've already exchanged one unit for another and I've swapped any number of guitar cables but the problem remains.