Audible Illusions Preamp

I would appreciate if someone can enlighten in chronological order which preamp in the Audible Illusions line that came out first and which is the current model from the L1, L2, 3A, 2C, (or any others I've missed). It would also be useful if someone can advise whether the sonic character is consistent throughout the range or there is a particular model that stands out from the rest in sound quality.

Thanks in advance.