I called the MOTU service (the guy's name is Josh) and we went thru the
"outlet changing test". I tested 4 wall outlets in my apartment, still there
was the buzz even without anything plugging into the MOTU.
The buzz is low and tiny, but according to you guys' words that it shouldn't
have that buzzing sound if I only turn out the machine itself, I took this
problem seriously. I even tried another power cable, well, again, the buzz
was still there.

The Motu guy took my name and told me to do some more tests: like
change to another apartment and try the outlets there....
He also told me if the buzzing thing doesn't change at more, I can fax my
reciept and the serial number to him and I will get a replacemnet.
I asked for the free-pick-up from them but he said I will need to pay the
shipping fee for ship back the item to them.
That's the whole story so far.

I will do more tests.

ORIGINAL: RRabbi

WOW.... so just from turning the actual MOTU on, without using any speakers or headphones you hear the buzz? that can't be good... mine certainly doesn't do that... Maybe try plugging it into a different power outlet, or if it's in a power bar try plugging it into it's own outlet by itself. I wonder if this is a power issue...

Dave

Go to your local MOTU Dealer, have them plug one in and see how it sounds in comparison. Take yours too.

Thats the way to do it. Im sure what your hearing is a PSU component dying. Get it checked out.

HOWEVER...I should say that Korg Tri series gear does make a similar noise. But if no other MOTU owners are hearing it, get it checked out!

sorry dude... i'm at work, and they won't let me do recording here... heh... I'll try later tonite...

so...no one trying to hear it??

Did anyone reach any conclusions on this?

Couple of thoughts:

1.) if your apartment building is old the wiring may not provide a proper ground

2.) if your apartment building is old, the electrical itself may be a.) overloaded and b.) noisy from microwaves, air conditioners, fan motors, etc. in other apartments or in the basement

3.) you have a ground problem in your computer itself -- perhaps a cheap or dying PSU?

4.) you have a CRT that is positioned closely to your machine and you're capturing EMI/RFI in the machine, in the MOTU, in connecting cables, whatever

Definately take your MOTU to a different building -- preferably the dealer -- and try to connect to a different computer, as you'll be able to rule out a whole bunch of environmental issues.

- Keith

Ok! Here are the follow up!

I ended up exchanged a new MOTU from the dealer (Full Compass, their services are really good!).
And now everything seems fine.
The MOTU is quiet, can only hear the tiny-tiny "z" if I "attach" my ear on the MOTU.

Keith: I agree with you that maybe my apartment is kind of old so it would affect the MOTU a little.
But I don't think (or maybe, no idea about) the PSU is dying or not because I connect the MOTU to
my new T41 Thinkpad. And it's with the LCD screen not the CRT.

ORIGINAL: cpa872

Ok! Here are the follow up!
And now everything seems fine.
The MOTU is quiet, can only hear the tiny-tiny "z" if I "attach" my ear on the MOTU.

OK good, glad to hear it! That sounds about the same as mine. Way to go.

OK glad you got it sorted.

FYI I get a nasty click sound if I turn on the PC when the MOTU is already running. Guess its something with the drivers. Just happens once when the PC starts up though.

Steve