The DBX 164 is a compressor/limiter designed for use in the recording studio. It's a really simple piece of gear, with only one parameter to work with. It's an older piece of gear, so it's got RCA connections and isn't balanced. You can however, set the level to either -10 db or +4 db. It comes in a single space rack mountable casing.
Even if you don't know a thing about the DBX 164, it's easy enough to learn how to use this without any help or hints. The only parameter found on the 164 is a slider for setting your compression level. So while you don't have much control over your sound, it's very easy to use and doesn't require too much background knowledge of compressor/limiters. A manual also won't be necessary...
The sound quality of the DBX 164 is definitely reminiscent of many of these classic DBX models. While you can't really get too many differing sounds, the sound that you can get is definitely useful for a few different applications. However, I've yet try it on anything other than a few different drums - snare drum, and tom tom drums specifically. I was definitely happy with the results I got when I ran drums through the 164, as you can hit it the signal pretty hard or subtly depending on how far over you set the compression slider. This isn't too versatile, so if you can't get a good sound off the bat, you're probably going to need to use a different compressor.
While not my favorite vintage DBX compressor, the 164 is still a very good compressor in it's own right. It has a nice sound that is perfect for getting a quick sound during tracking or mixing. Anyone will be able to use this without any problems since it's so simple, but getting your hands on one of these could prove to be somewhat difficult. If you can ever find a 164 either used or in a studio, it's definitely a piece of gear that I'd recommend at least trying out if you're into older compressors, as DBX is a company who definitely knows what they're doing...