Yamaha DTXpress/DTXplorer/DTXtreme

Hi There,

I have just bought a DTXpress kit and I love it!  I have not even got 
close to exploring all of it but I have one question that I hopt 
someone can answer for me.

I bought a good set of Headphones (Sony Eur 85) and when I plug them 
into the Brain and play I find the volume to be quite low! When I am 
doing some hi-hat work I can here the sticks hitting the pad quite 
clear!  Does any body know how to increase the volume through the 
headphones so I can not hear the pads being hit?

By the way I have the volume on the Brain at full!

Thanks

Brian from Ireland.