After having a few cheap m-audio interfaces, I switched to a tascam US-144mkii. With my m-audio's, I always connected it to my macbook pro (all drivers updated, lion, 8gb ram, 500gb 7400rpm, 3.06ghz intel core 2 duo) powered on and there was never any problem.
With the tascam US-144mkii, when I connect it with the macbook powered on, I get a lot of 2-4khz "high-pitched clicking computer interference noise". Only way I can get rid of it is if I connected it with my macbook powered off, then boot it up. It's fine then, but again, if I connect it at anytime with the macbook on, it gives that "computer interference noise".
I called Tascam, and the guy says to always have it powered off when connecting their devices, otherwise to have problems is going to be "normal". I asked him if this was a requirement as the m-audio's don't do it, and no where in the paperwork does it state to have it turned off. In fact, on page 15 in the manual it says to "restart the computer and THEN connect the unit".
My question is, do I have to have the computer off to plug in an audio interface? does it harm the computer or the interface?
