question about sampling into the mpc 3000, input problem

i have a question about sampling into the mpc3k
ok look when i come out of my tascam m216 mixer into my mpc3k inputs and turn up the corresponding channel, i get a high pitch whine that makes my dog howl....
no kidding
now this doesnt happen when i sample into my asr10 or my triton so whats the deal...
i dont think the inputs on the mpc are fried because when i use drums i sample on the asr and the resample them into the mpc via the asr 10 outputs the signal is fine and i dont hear that sound...
can anyone tell me whats up??
p.s. the input gain on the mpc is always set to low just in case..

appreciate any help
thanks

turn monitor off on the sample screen.

yeah, u got a loop

id turn off the lines on your mixer that your mpc is plugged into and monitor on your MPC so u get a clearer sound of the sample