slight high pitch squeal thru input echo monitoring...

Im proud to say that I can record 18 track in @ 96/24 using the input echo for monitoring on all channels without latency...WOOHOOO!!!!... The machine I built for the studio has been labeled SKYNET (The Terminator)..It will eventually destroy the world !!! LOL...any way I do notice a low volume squeal in the headphones when using echo for monitoring...It almost sounds like its a ground issue.. It also pick up the motor noise in the fader.....when using direct monitoring (which is limited) it's not there..It is also NOT coming thru to the recording..the recording is pristine !!! Just thru the outputs which i route to a headphone breakoput box... How I get my headphone sends is I use the 1thru 8 output driver...and send an individual track send to each output that requires that track in the headphone mix for individual headphone mixes... I love the idea that I can send up to 20 separate mixes... If you can tell I received my second V700R..
Any one know what the squeal is?? Its not unusable because of it but,   it is slightly destracting.