In defense of AI--I've owned a Contra, a Clarus (just sold) and now a Focus--I wouldn't necessarily blame a muddy boomy sound on the pre-amp section of the Clarus. I've found that it is much more a function of the pickup and the particular bass. While I know that lots of people have had good luck with the Realist, and the modifiied Realist that is on my Eminence sounds fine through the AI gear, a Realist on my Hatchez carved bass sounded like total crap. Just like posted above, it was muddy and dark and boomy. The only way I could get any kind of acceptable sound was to turn the bass control and mid controls almost totally off, and even then it didn't sound very good.
Once I took the Realist off and replaced it with a Schertler StatB, the sound through the AI gear became absolutely beautiful--accurate, not boomy, woody and natural. I continue to get compliments on my amplifed sound, and have had no trouble with getting a good natural sound out of AI amps. While there is nothing wrong with carting around a preamp to use with the AI gear, I've never wanted to do that since I've found it is just one more thing to carry, leave behind and service. I like my rig to be as simple as possible. You might also spend some time experimenting with which one of the two input jacks on the AI basses results in the best sound for your particuar instrument and pickup.
For bass guitar, the Focus is also incredible--loud, warm and sort of tubey--I'm not sure yet if I'm going to begin the use the Focus instead of my WW Ultra, and I need more gig experience with both amps before I know the real nature of the Focus.
Erik Hansen
Los Angeles