As you may recall, we installed an Aviom Personal Monitoring System a while back. Click here to read more. Honestly, I love the system, with one exception; since A-16I does not supply power, you have to have all the individual mixers powered with wall warts. This isn't that big of a deal, as it's our backline on ears anyway, and we have power to every location already. However, during one rehearsal (that already wasn't going well...), suddenly the bass player announced he had nothing in his ears. Same for the drummer. I ran to the stage to check it out and found the personal mixer at the bass location dead. Check the cables, looks good. Check the drummer. Same thing. Root around a bit and discover the wall wart came unplugged when the drummer stepped up to the drum platform a few minutes earlier. Ugh... Since the system is daisy chained, once one goes down, the rest after that go down too.
Enter the A-16D (and it's bigger brother A-16D Pro). Basically an ethernet power-over-ethernet switch, it allows you to take the output of the input module and wire the system in a star topology instead of daisy chained. Each mixer is fed with it's own cable from the switch (the A-16D, which looks a lot like a hub, or even a router, but it's a switch). The A-16D acts like an audio distribution amp, taking one signal in, and sending out 8 identical copies of that signal. As a bonus, it also sends power down the Cat-5e cable, eliminating the wall warts (and the possibility that one will come accidentally unplugged).
The box itself is a 1/2 rack space unit with 9 RJ-45 connectors on the front (1 in, 8 out), and 9 power ports on the back (9 in, one to power the unit, and 8 to power each port). That's the first disappointment I had when I opened the box. Given that at 24 port POE (power over ethernet) switch from D-Link can be had for under $200, I expected this $325 8 port switch to have a beefy power supply to power a mixer from each port. Instead, you have to use the wall wart that came with the mixer to power the port. And it only powers one mixer from each port. You can still daisy chain, but after the first mixer, you'll be back to wall warts. It's not a big deal, except that a power strip or rack power distro is needed. And since most rack power distros have 8 outlets, and the unit needs 9 to fully run, you'll need a power Y-cord to fully utilize the unit.
Aside from that, the unit works as advertised. Since each port buffers and re-sends the digital signal, you get 8 exact copies of the output of the A-16I (or whatever input module you use). It's been rock solid since we installed it, and not having wall warts on stage has been a real plus for keeping things neat. I built a simple 4 rack space box to house a Panamax power distro, and simply screwed the A-16D to the bottom of the rack, spacing it off with washers. The bottom of the unit is tapped for such mounting.
It should be noted that the A-16D Pro is rack mountable (2 spaces high) and includes a standard IEC power cord, uses EtherCon connections and does not require wall warts. On the other hand its nearly 3x the cost. Is it worth it? You be the judge. For my money, I'd buy one A-16D and 2 more A-16II personal mixers. I'll live with the individual power supplies for each port.