Yamaha DTXpress/DTXplorer/DTXtreme

Hi all,

Have recently purchased the above and after about two hours of playing, 
for no reason, the volume of all pads has decreased to the point of me 
almost not being able to hear the sounds at all. The problem is not 
fixed by performing a factory reset and appears to have also affected 
the sound of the drums when listening to the built in songs. It almost 
sounds as if there's loads of reverb which is whiting the sound out - 
I've tried bring this level right down but then the noise heard is even 
quieter.

I'm at a total loss! Any suggestions?

Thanks

nbp