I have a Tech 21 Killer Wail wah that I love, except there is 1 problem. Whenever I play at this one specific venue my pedal makes a loud screaming type noise when I engage the wah. It makes that noise when I have it at the toe end and not not the heel end. Any other place that I use it there are no problems at all. I don't understand. Help! Thanks!

I run it on a pedal board with several other pedals. All which I never have a problem with.
Mesa Boogie Dual Rectifier
Vox Valvetronix
Gibson ES-335
Gibson SG Standard
Taylor 214CE
Tech 21 Killer Wail Wah
Digitech Whammy
Small Stone Phaser
Boss DD-20 Delay
Line 6 Verbzilla
Are you sure it isn't feedback? I just wonder because when I have my guitar facing my amp and have a lot of gain and my wah engaged I sometimes get feedback