serious 8-outs problem (mutec)

I recently bought the 8-outs from Mutec, found it east to install and understand, but I have a serious problem.
I have my outs going to a mixer that I believe is trouble free (so fingers are pointing at the mutec board).

While playing a tune it keeps throwing out VERY MUFFLED samples, not all the time maybe every 8th or tenth sample the MPC plays, has a MUFFLED (or badly filtered) sound to it?????It sound awfull, and apears to be compleatly random, but rarely can it play 8 sounds without this problem..
But the other day I had a compleatly trouble free day, no bad sounds (and this is playing the same tunes/same settings/outputs ect..).

Has anyone had or heard of this type of problem????
any advice PLEASE.......

peace
parkz

I think Iv been barking up the wrong tree, Iv been runnin individual outs straight into my HIFI and they have been playing perfect, put them back into the mixer and they are shit....Looks like the mixer is going back to the store..

parkz