Does anybody know the difference between Equivalent Input Noise and Interchannel Crosstalk when it comes to preamps?

No, I don't. When you buy very good to great preamps you NEVER have to worry about such things. When your shopping for preamps that are in the crap catagory, specs are not going to tell you anything about how the preamp sounds which is far more important even though you are still going to be stuck with a crap preamp. From your short list, I'd be willing to bet and expect that the dbx would likely sound the best.

Yes, the difference is this..

EIN, is the Equivalent Input Noise. It says that at a particular gain setting (usually, if it's cheap gear they'll measure at max gain to bias the spec upwards), with the input shorted through a nominal resistance (usually 150 to 200 ohms to simulate a mic, but again you can cheat the spec by going to a lower resistance), measure the output noise level (and maybe cheat again by using a weighting curve) relative to a standard (like 0 dBV), and determine what the equivalent input noise was. In other words if at 60 dB of gain and the input shorted through a 150 ohm resistor and you measure -52 dBV, then the EIN is -112 dBV.

Interchannel crosstalk refers to how much of channel A can be expected to get into channel B. I'm not sure of how to measure it in a standardized way, but you could run a signal with 0dBV output voltage in one channel, and turn up the gain full on the other channel, and meausure the cross talk.

But there are so many ways to cheat the specs and get good results...it's best just to use your ears.

Cheers,

Kris