I have a few DBX units connected to my multi-track reel machines, but none of them are easily switchable to play DBX-encoded LPs. I don't have many, 18 or 20 of them, but I remember that they used to be fun to play with (before the CD made them pretty much obsolete). I was bored the other day, so I picked up an entry-level NX40 unit on a whim.
I have to say that it isn't as cool as I remember. I don't have a problem with surface noise anyway (keep your LPs clean and use a decent turntable), and most LPs have enough dynamic range with a decent phono cartridge and tonearm. Kind of fun to play with, but if you have any fairly deep clicks and pops they have the potential to be huge.
Being a compander system, any signal below a certain threshold (tape or record hiss) is quieted, but anything louder than the threshold can become much louder. I only have a couple of marginal DBX LPs, and they are generic "demo" disks. Anybody else play with these in the past (or present, if you care to admit it)?