Firewire & bus powered devices - Phonic FireFly 302 Plus

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Firewire & bus powered devices - Phonic FireFly 302 Plus

Hello Appleheads,

Looking for some help if you have a spare moment.

I just purchased a Phonic Firefly 302 Plus audio interface, and even though it is supposed to be able to be powered by the firewire bus, I am unable to get it to work. The unit's power light does not come on at all, however when using the external power supply that is also supplied it does work. I have tested two firewire cables, 1 of which I know works.

Are there any tricks to get this to work? Can you change power output settings for firewire ports somewhere in the system?

I am using a 6 circuit firewire 400 cable that came with the device. This is the only firewire device connected to my computer. The computer is connected to a power supply. Running OSX 10.6.4.

My Macbook Pro...
Model Identifier: MacBookPro4,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.4 GHz

Thanks for any help that anyone can provide.
Hartz.

Macbook Pro, Mac OS X (10.6.4), i luv my mac

Posted on Jul 7, 2010 12:39 AM

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Answer 1

Jul 7, 2010 3:26 AM in response to Hartleigh

Is the Phonic device Mac compatible?

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Answer 2

Hartleigh Author

Level 1

10 points

Jul 7, 2010 4:01 AM in response to DaddyPaycheck

Hiya,

Yes the device is mac compatible according to the product site.

http://www.phonic.com/en/firefly-302-plus.html

Cheers.

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Answer 3

eww

Level 9

53,052 points

Jul 7, 2010 4:13 AM in response to Hartleigh

Two things, both so obvious that I hope you'll pardon me for mentioning them:

The device has two FireWire ports: one four-pin and one six-pin. To run it on FireWire bus power, you must use the six-pin FW port. A four-pin FW port doesn't carry power — only data.

The unit also has a three-position power switch: DC-in, Off, and Bus. That switch must be in the Bus position to draw power from the FireWire bus.

Make sure you're doing these two things right. If you haven't been, then it's time to read the documentation for your interface. If you have been, excuse me for belaboring the obvious.

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Answer 4

Hartleigh Author

Level 1

10 points

Jul 7, 2010 4:35 AM in response to eww

Hi eww,

No problems at all. I provide IT support for end users myself and understand that sometimes people miss things like that.

I am definitely using a 6-pin firewire 400 cable and the power switch is set to BUS. It's just like it is not getting any, or enough, power.

Cheers.

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Answer 5

Jul 7, 2010 4:44 AM in response to Hartleigh

I've personally not had much luck with any audio interface (or hard drive for that matter) that was powered via a bus, whether or not it was USB or FireWire. The preamps alone can draw fairly hefty amounts of juice.

If you must, for whatever reason, power this device via the bus I suggest that you get yourself a powered hub and put that between the Mac and the interface.

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Answer 6

eww

Level 9

53,052 points

Jul 7, 2010 5:33 AM in response to Hartleigh

It's just like it is not getting any, or enough, power.

I agree. Do you have access to any other FireWire bus-powered device with which you could test the port to see whether it's delivering any power? If it is, then I suspect the interface is drawing more than it's supposed to, and exceeding the power allowance that can be drawn from the port. In that case, you'll just have to run it on AC power.

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Answer 7

Hartleigh Author

Level 1

10 points

Jul 7, 2010 1:33 PM in response to eww

Hiya,

Thanks for your help on this.

I have successfully used a portable 2.5" external HDD on the same firewire port recently, it is definitely putting out at least some power.

*scratches head*

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Answer 8

eww

Level 9

53,052 points

Jul 7, 2010 4:19 PM in response to Hartleigh

scratches head

With your other hand, you might just try that drive once again and make sure the port is still putting out power.

If it is, then I'm afraid AC power is going to be the answer. You might lodge a polite complaint with the maker of the interface. They will undoubtedly blame it on Apple, Apple will blame it on them, and you'll be stuck in the middle using your power brick.

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Answer 9

Hartleigh Author

Level 1

10 points

Jul 8, 2010 1:51 PM in response to eww

The unit works fine with DC power. I am yet to test it on another computer to know for sure.

An interesting point has been raised to me though that has been discussed here: https://www.mhsecure.com/faq/index.php?action=artikel&cat=3&id=21&artlang=en&hig hlight=bus power

+The MacBook Pro models include protection circuitry to shut down the bus power when a device's inrush current amount violates a threshold. This issue affects the startup transient only, so you can power the MIO from its power supply to boot the box, then connect the FW to the computer, and remove the MIO power supply after it has joined the bus.+

Surely this threshold would be set to the maximum voltage provided on the bus? 12v?

Either way I have decided that I will just use the DC adapter.

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