#MAC PRO POWER SUPPLY TEST PORTABLE#
#MAC PRO POWER SUPPLY TEST MAC#

#MAC PRO POWER SUPPLY TEST MAC#

We've tested this off a powered Mac port and were able to run two CFFire800 Pro's without the addtional power supply. A notible exception was the CFFire800 Pro FireWire 800 UDMA CompactFlash reader with Unibrain's 3 Port FireWire 800 Hub. The calculation above are the worst case scenario, typical application rarely see devices drawing current of each port.

When a company lists Watts for their FireWire ports, divide it by 12 (FireWire is typically 12 Volts) to find the Amperage. Often computer companies will list ports by watts, instead of amps. Unibrain FireRepeater-800 Pro FireWire 800 IEEE 1394b Repeater Hub 5 Port (3 amperes) / 5 = 0.6 amperes approximately per port (max) Unibrain FireRepeater-800 Pro FireWire 800 IEEE 1394b Repeater Hub 4 Port (3 amperes) / 4 = 0.75 amperes approximately per port (max) Unibrain FireRepeater 800 FireWire 800 IEEE 1394b Repeater Hub 3 Port (3 amperes) / 3 = 1 ampere approximately per port (max) Unibrain FireRepeater 400 FireWire 400 IEEE 1394a Repeater Hub 3 Port (3 amperes) / 3 = 1 ampere approximately per port (max) In the case of Unibrain's FireRepeater 3A supply, this would work out approximately as follows: Further, the total amount of Amps a hub provides needs to divided by the number of ports to find per port current when each port is drawing current. If you daisy chain several devices, it also may draw more current than available. Д«us Power isn't always enough for multiple devices drawing current off multiple ports at the same time. Conversely, if you are using bus powered FireWire products, you almost certainly need the optional power supply. If you are using self powered devices with a FireWire repeater hub, then there isn't a need to purchase an optional power supply.

#MAC PRO POWER SUPPLY TEST PORTABLE#

Portable devices like the Apogee Duet require bus power as well. Our CFFire800 Pro FireWire 800 UDMA CompactFlash reader requires bus power. FireWire hard disk drives using 2.5in mechanisms are typically able to use bus power. Most FireWire based audio equipment like those from Pro Tools is self powered as wellД«us Powered FireWire devices draw current from the FireWire bus itself. Another example are battery powered DV Camcorders. One example is FireWire hard disk drives using 3.5in mechanism which come with their own power transformers and AC adapters. Self Powered FireWire devices are ones that plug into the wall or utilizes internal batteries. A frequently asked question about FireWire repeater hubs is 'do I need the optional power supply?' The answer to this question depends on the types of FireWire 800 or FireWire 400 devices are being used.

Mac pro power supply test