The Apogee Electronic AD-16X is an analog to digital converter. At the studio I use this in, we have it locked into the Apogee Big Ben that runs with a Digidesign 192 I/O audio interface to run Pro Tools HD. The AD-16X has 16 channels of converters in the form of both ADAT and AES. It also has a world clock in and out and is powered by your traditional AC power cable. The unit is pretty easy to use, and since I have it synced up with another converter and audio interface, I pretty much leave it as is and gives me a great high quality conversion on up to 16 channels of audio! For me, this is a huge asset as I'm not a huge fan of the converters made by Digidesign, and these are a great replacement.
I've been using the Apogee Electronic AD-16X analog to digital converter for about a year and I've been quite pleased with the results that I get with it. It is easy to use for what I do with it and is an awesome substitute for Digidesign's converters. This being said, these aren't cheap, as they are a huge quality converter from a highly trusted company. I would recommend this not only to professional studio owners with any type of rig, but also for the home studio owner looking to bolster their chain with a great converter like the AD-16X. I can't say enough about how clean the signal is from not only the AD-16X, but from all of Apogee Electronics converters. While these aren't for the studios out there on a tight budget, for those looking to put together a superior Pro Tools rig with the highest quality convetors available, a converter of this quality is a must. I highly recommend checking these out if you're looking for a analog to digital great converter.