can you hear litlle artefact from spdif out

hi,

for the first time, i'm using really precisely my mpc 1000 spdif output's.
i'm trying to record a really filtered sound which hasn't a lot of harmonics (pad made of sinus) and i can hear little artefact.
i use a motu traveler soundcard.
can you hear that, schould i report it?
i've listened the same thing with my headphone socket and with the main out thrue a mackie mixer, the problem doesn't occur...
i've also tried different buffers settings...

(please don't delete this topic i need an answer before putting it in the bug report topic, thanks...)

thanks for the replies

Does it sound like a little blip of static that comes in every few seconds? If so, you need to sync your digital clocks.

Set the MOTU's digital clock source to EXTERNAL.

i have this problem to but i can't set the clock to external in the setup panel.
i'm speaking of short clitches on this one...

i don't have any external settings

on the front of the traveller:

1. press 'Setup' knob.
2. turn 'Value' knob till display reads:

Clock Source:
SPDIF 44/48