iMac Firewire 800 + Apogee does not provide enough phantom power for mic

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8 points

iMac Firewire 800 + Apogee does not provide enough phantom power for mic

I have a new 2009 iMac and an Apogee Duet, connected with a basic Firewire 400/800 cable, and am unable to use my Blue Dragonfly microphone with it. I am running two mics through the duet into Garageband '09 - a Blue Bluebird mic and a Blue Dragonfly mic. The cheaper Bluebird mic works fine, but the Dragonfly mic won't work. I already tested the Dragonfly at the store and it works fine with a Mac Pro firewire port at the store. Because the Dragonfly (unlike the Bluebird) has a MINIMUM phantom power voltage requirement, it seems that the iMac Firewire 800 port (as translated down to Firewire 400 by the connecting wire) isn't providing sufficient phantom voltage for the Dragonfly. Has anyone else had this issue or know a way to solve it? Is it a known issue that the iMac's Firewire 800 doesn't provide as much power as other Macs?

iMac, Mac OS X (10.5.7)

Posted on May 17, 2009 4:53 PM

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Answer 1

May 17, 2009 5:48 PM in response to sbriffe

sbriffe wrote:
I have a new 2009 iMac and an Apogee Duet, connected with a basic Firewire 400/800 cable, and am unable to use my Blue Dragonfly microphone with it. I am running two mics through the duet into Garageband '09 - a Blue Bluebird mic and a Blue Dragonfly mic. The cheaper Bluebird mic works fine, but the Dragonfly mic won't work. I already tested the Dragonfly at the store and it works fine with a Mac Pro firewire port at the store. Because the Dragonfly (unlike the Bluebird) has a MINIMUM phantom power voltage requirement, it seems that the iMac Firewire 800 port (as translated down to Firewire 400 by the connecting wire) isn't providing sufficient phantom voltage for the Dragonfly. Has anyone else had this issue or know a way to solve it? Is it a known issue that the iMac's Firewire 800 doesn't provide as much power as other Macs?

I've heard similar things about some devices claiming to provide phantom power that don't provide the full 48v.

Is Apple able to provide specs on the power flowing through the firewire port of the iMac vs. the Mac Pro? If they are theoretically the same, then maybe there's something wrong with your iMac. I'd also wonder what Apogee has to say about it. I'd call them, if only to see if they've encountered it as an issue with the iMacs before (Apogee is pretty good with tech support). After all, the iMacs share a lot of components with laptops, and a lot of people use Duets with laptops, so Apogee might have run into this before.

If it turns out that nothing is broken and therefore nothing can be fixed, a workaround would be to use the Dragonfly with an external preamp with sufficient phantom power and plug the preamp into the Duet at line level. But that kind of defeats the elegance of the Duet.

I'd also think about posting something at Gearslutz, which has a lot of Mac+Apogee users on it:

http://www.gearslutz.com/board/music-computers/

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Answer 2

sbriffe Author

Level 1

8 points

May 17, 2009 7:01 PM in response to MattiMattMatt

Thanks, I just bought a stand-alone phantom power unit that I'm going to put between the mics and the Duet, will post an update if that works and if I can find out anything from Apple/Apogee. I actually brought my Duet into the store as well to and it worked fine hooked up to their store display Mac Pro. So the only options remaining in my mind are (1) the iMac Firewire doesn't put out enough power in general, (2) the iMac doesn't put out enough power when stepped down to Firewire 400, (3) my particular iMac is defective. I just returned a Firewire 400/800 adapter that I had attached to the end of the included Apogee firewire cable, thinking that was the problem, and replaced it with a 6-foot Firewire 400/800 cord from Tekserve, which is even worse and reduced the Dragonfly signal from very, very low to zero.

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Answer 3

sbriffe Author

Level 1

8 points

May 17, 2009 7:06 PM in response to sbriffe

Also, I should add that the previous little adapter piece WAS a problem too; when we tested that in the store with the Mac Pro, it killed the signal from Dragonfly. I think the Dragonfly really needs the full phantom power voltage to function, and either the iMac, the Apogee or the combination is not providing enough. I'm going to call Apple about this and will post any technical specs I can get from them.

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Answer 4

May 17, 2009 7:23 PM in response to sbriffe

sbriffe wrote:
Also, I should add that the previous little adapter piece WAS a problem too; when we tested that in the store with the Mac Pro, it killed the signal from Dragonfly.

Does that mean you used a different cable in the store with the MacPro that you haven't used with your iMac? Since you had problems with both the Tekserve cable and the adapter, maybe the cable is the culprit, and the one that worked in the store would also work with your iMac. Just a thought.

Also, I take it you didn't get a chance to try it out with an iMac in the store. If you got an iMac in the store to work, that would at least narrow it down to yours being defective, or alternatively confirm a universal problem.

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Answer 5

sbriffe Author

Level 1

8 points

May 17, 2009 7:54 PM in response to MattiMattMatt

Unfortunately the Guitar Center I was at only had a Mac Pro set up. I first used the Apogee FW400 cable + adapter, that didn't work. However, the cable that Guitar Center had did work with my Duet. So I went and got a new cable at Tekserve and brought it home, but now the signal is worse than before. So at this point I think the cables/adapters are degrading the power, but the basic problem is probably the iMac's power output. Or I may have bought a cable that is equally deficient to the adapter I was using at first in terms of transmitting phantom power (both were from Tekserve). I may go do that at the Apple store or try to find someone else with an iMac, I'll definitely do it if the new external phantom power unit doesn't fix this.

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