Noise problems with new Vox AC100CPH Classic Plus

[Rooben]

I just got a new Vox AC100CPH Classic Plus, and it sounds pretty amazing. I know it works because generally the sound is crystal clear. However, it only works if there are no other bands at the warehouse where my practice studio is. When other bands are plugged in and playing, I can hear their instruments coming through my amp, as well as FM radio stations and cell phone conversations, not to mention an incessant hum. I did some process of elimination stuff, such as moving the amp, and removing some and then all of my effects pedals, but to no avail. Everything I use seems to work, because when I plug my setup into another amp, there are no problems.

Anyone have any insight and/or advice on this? Thanks for your help.

[Enzo]

Thinking that perhaps the wiring in your old warehouse is pretty old, and your amp is plugged into an outlet that is a long way from the earth ground.

Also, does your guitar have to be plugged in for this to happen? Can you hear this with NOTHING plugged into the input? And with the guitar ONLY plugged in, if you turn the guitar volume knob to zero is the noise still there?