Solid State Logic Alpha-Link MX 16-4 Xtreme 64 by Ziga
First my background, for the rest of the review to make a bit more sense. I'm a semi-pro recording/mixing engineer with a small facility that evolved from a home studio. Nothing huge and expensive, but still not the typical home studio any more.
I've bought these converters after owning first an RME unit and then the AlphaLink AX 24i/o for a short time. I've also used and heard the Digi/Avid blue and black HD i/o units, Apogee AD-16X, and regularly work on Studer Vista and Lawo Mc2-56 consoles, which are broadcast oriented units but still cost an arm and a leg and sound fantastic.
The SSL converters sound amazing in comparison to all those up there in the previous paragraph, at a very, very attractive price. What struck me at the first listen was the accuracy of the sound field, the spatial placing and the reverb tails. That, I think, signifies a good clocking architecture and careful design of high frequency parasitic phenomena and filtering.
The unit is probably not the most transparent out there, but still not as "euphonic" as an Apogee for instance. This is not a serious colour by any means, but every converter seems to have it's own character in spite of the usual copy-paste flat frequency response. The MX unit has that lovable solidity in the low to low-mid spectrum, the hi-mids are very transparent sounding with no distinctive character and the highs are smooth, but not "clouded", which again points to a good clocking.
Another aspect of converter quality is the handling of transient-rich material. Compared to the Apogee, it's not as fat sounding, but I don't always take that as a bad thing. The low end is still there all the way down, but it's not hyped or coloured (typically SSL :P). It's not the most "snappy" sounding converter out there, but this could mean the lack of harmonic distortion, which in a converter is a good thing, but after recording with Earthworks microphones as overhead mics, I couldn't but laugh at the sight of those spikes, high and clear and able to crack your skull in half after applying some moderate VCA-style compression.
The sound quality gets a 4 from me solely because of the fact that there are better sounding units out there, albeit with a significantly more burdening price tags.
Feature-wise the unit is very straight forward: analogue i/o on Tascam-standard wired DSUB-25 connectors (thoughtfully clearly mapped in the users manual for those who know how to solder and consequently don't want to spend some ridiculous amount of money for DSUB-to-XLR looms), clock i/o on two BNSs, MADI is optical only (that's why I gave it 4/5, someone might want a BNC option as well) and there is also an USB port for firmware updates, and those actually come from time to time, the last one making the unit go up to 4xfs (176.4kHz and 192kHz). Front panel controls are so simple even your drummer would figure it out, the only thing that I would welcome would be a small LCD display with some more elaborate metering, but that would probably just make the price much less attractive for a job that the existing three-colour LEDs do perfectly adequate.
All in all this is a great unit that strangely just doesn't get the press and popularity that it would definitely deserve for the sound it offers for the money. For a grand, you just can't get 16 inputs and enough outputs for a small facility at that quality and if I dare say, you would have to spend somewhere around 3-times as much to get an audible difference, so I'ill, again, call it some serious bang for buck unit!