mpc 1000 playback issue

hi folks...

I am a new user to the mpc 1000 but here is what I did...

I ripped 10 seconds from a song off a cd....I then converted it into a .wav format and uploaded it into the mpc 1000. I trimmed the file into 16 parts and played it back with no issues. I created a simple track. everything sounds good so far.

now I loaded in some drum samples and recorded another track on the mpc 1000.

the issue I am having is that if I play these tracks in solo they sound fine. if I have both tracks playing simulataneously it does not sound right. I hear some weird clicking sounds and i do not hear the tracks properly.

any ideas what may cause this?

thanks....