Let me get this straight, do NOT power an mbox 2 pro from it's power adaptor?

[BGMusic]

So never power the mbox 2 pro from it's own power adapter when running on a firewire bus with it's own power. I would've thought the power adaptor would help the mbox 2 pro to run better.

[bfx]

Is that a question or the answer already?

Anyways, I'd say the General Troubleshooting Thread is pretty clear:

You should NOT use the AC adapter for the Mbox 2 Pro unless the firewire port on your computer doesn't supply power - for instance, if it's a 'mini' firewire port with only 4 pins.

[stratquebec]

Originally Posted by bfx

You should NOT use the AC adapter for the Mbox 2 Pro unless the firewire port on your computer doesn't supply power - for instance, if it's a 'mini' firewire port with only 4 pins

Well, why???

[bfx]

Short answer: Because!

Longer answer: Imagine feeding a light bulb with more power than it actually needs. It can't say no, can it? Now think of doing that to your precious MBox 2 Pro or whatever. I guess with a little more budget Digi could have made the MBox say no. But obviously it can't. Although it's quite possible that your MBox survives the procedure the greater amount of power could make some internal ICs go nuts. Hence the errors.

You guessed it already: I am not an electrical engineer myself.

[stratquebec]

Hi bfx!
I'm not an electrical engineer too but I don't think you're injecting more current in your MBox2 Pro with the power supply and the firewire cable plugged in at the same time. The device can be only powered by one and only one source of power. One should disable the other, I presume.

So to me, if there is a reason, it's not that one. Anyway, using the firewire OR the power supply power, not both at the same time, is certainly what we call common sense!

[bfx]

Anyway, using the firewire OR the power supply power, not both at the same time, is certainly what we call common sense!

Hmm, somehow I have the feeling the GT thread got that extra post for a reason...

The device can be only powered by one and only one source of power. One should disable the other, I presume.

Yeah that's what you presume - no offense. Maybe it's even supposed to work the way you presume but still something gets messed up deep inside the machine... Heck, I did not build this thing nor do I have insight into the blueprint. I'll shut up now. zzzzip.

[stratquebec]

Originally Posted by bfx

Hmm, somehow I have the feeling the GT thread got that extra post for a reason...

Yep but certainly not the one you're giving -- no offense!

[nucelar]

IMO bad electronic engineering practice. (I'm an EE)
One supply should cancel the other electronically. If both connected, external should be used.
Also the led feedback is counterintuitive. If the power comes from the adaptor, the led lights green (green is associated with "OK"). If the power comes from FW, the same led is Orange (orange="warning"). If both are connected, the led goes green again (OK) but it's not OK!!!
IMO it should be green when powered either way and flash orange when both connected at least.

Another flaw that caused me MAJOR headache is that when I first connected the Mbox 2 PRO to the computer, it apparently went through an automatic firmware update during which NO signs of life whatsoever are given. The power led was OFF (although connected to power) and I thought the unit died in my hands the first day.

Also, on my unit, one of the pots is much harder to rotate than the others, apart from being highly uncomfortable to use...

Really un-pro design...

[bfx]

Now I am interested – why certainly not?

[stratquebec]

Originally Posted by nucelar

IMO bad electronic engineering practice. (I'm an EE)
One supply should cancel the other electronically. If both connected, external should be used.
Also the led feedback is counterintuitive. If the power comes from the adaptor, the led lights green (green is associated with "OK"). If the power comes from FW, the same led is Orange (orange="warning"). If both are connected, the led goes green again (OK) but it's not OK!!!
IMO it should be green when powered either way and flash orange when both connected at least.

Another flaw that caused me MAJOR headache is that when I first connected the Mbox 2 PRO to the computer, it apparently went through an automatic firmware update during which NO signs of life whatsoever are given. The power led was OFF (although connected to power) and I thought the unit died in my hands the first day.

Also, on my unit, one of the pots is much harder to rotate than the others, apart from being highly uncomfortable to use...

Really un-pro design...

So now we, and the OP, have a real clear answer now! Thanks nucelar. You rock!