Apogee Electronics AD-16X by RobAnderson
The Apogee AD16x was the successor to the AD16, both of which featured 16 channels of excellent analog-to-digital conversion in a single RU. The original AD16 was about as simple to operate as could be, the AD16x was a bit more complicated to operate, but added some very nice features.
Out of the box, the AD16x had 4 lightpipe and 16 AES/EBU outputs. At lower sample rates, the two sets of lightpipe outputs function redundantly as two sets of 16 out; at higher rates they would switch to SMUX operation. The 16 analog inputs utilized DB25 connectors.
The main addition of the x-series was an expansion card slot that could allow the converter to operate as an interface to a computer, allowing to operate as a front end to a Pro Tools HD rig, an Apogee Symphony rig, or even just as a generic Firewire interface. Running in advanced mode, it could provide D/A functions as well.
The internal clock was the same as the Big Ben master clock. A handy Softlimit function gave some peace of mind when tracking, or allowed you to push the input levels a little hotter without concern. UV22 dither was available for bit depth reduction.
For location recording, both AD16's offered features that were hard to beat: redundant outputs, soft limiting, 16 channels in a single RU chassis. While other high end converters might offer a bit of a sonic edge, the AD16x was no slouch, easily beating out the stock converters on some highly regarded hard disk converters.
While I did miss the simplicity of the original, the advanced feature set of the x-series proved very attractive. Why Apogee stopped making the AD16 line is beyond me, especially with the releases of Pro Tools 9 & 10, as well as Benchmark's recent offering of a single RU 16-channel A to D.