Is anybody having trouble using this thing? I tried it once with an Ace250 headphone worked great...any other headphone...I get the audible speaker even though the converter is connected to the device. I am using a 3.5mm to 1/4" converter jack and doesn't seem to want to work. The At Pro headphones work just fine with it but, man they're heavy and in hot weather...they're a little too hot on the noggin. Any comments or suggestions? Thanks.