What can you tell me about First Sound pre-amps?

Kalan:
One more thing. My rack is the Finite Elemente Spider -- which doesn't have any shelves to speak of. The equipment sits on elastometers that fit onto the wooden legs of the stand, so there's no sound bouncing between shelves. Ingenious solution, I must say! The equipment sits in "open air," so to speak. Nice rack, much better than the Billy Baggs, which sounds "dark" by comparison, and "heavier," too. The music seems freed up on the Spider and more delicate.

Mphnkns, So you have the outlets and shelves covered. Good. Did you mentioned in another response whether you're using a power conditioner or power strip of some sort? If you are, by pass it and go direct from the wall.

Could you please tell me (again, if you've already said) what power cord(s) you're using on the First Sound---and what the power cords are elsewhere in your system for that matter? If you have access to Silent Source power cords, give them a try.

Also, what model of First Sound are we talking about? (Sorry if you're repeating things, here...)

The only other thing I can think of is that guidocorona's suggestion of the 'cuivre' phenomenon on brass may be coming through with the First Sound in such a way that happens to mesh right in with the rest of your system's qualities so as to make it more apparent than with other pre-amps.

Your case is an odd one. I have found that the First Sound pre-amp is neutral, and it seems to be sensitive to system integration issues possibly more than some other pre's.

Kalan:
Ive used quite a few power cords. I think it isn't likely that that's the issue. Transparent, Nordost, Shunyata, PS Audio. If none of those work, that's not a compliment for the First Sound. Emmanuel, by the way, LIKES the Shunyatas, so that scenario doesn't work.
And you can be sure that I've covered all the bases with Emmaneul over line conditioners, and whether or not to use them with the FS (he says NOT).
The system integration suggestion may be the truth. I would then suggest that a preamp that can only work with very specific cords, interconnects, amps, etc. might be an issue in itself.
In case it is not clear, the earlier version of the FS sounded equally edgy, BUT it SEEMED more powerful from the upper bass down. That may have been the Shunyata King Cobras, of course. Hard to say.
In any case, the unit, which I do like, still seems leaner to me than it once did. It's my experience that leanness and extreme detail go together. Is yours different?

MPHKNS, I still hold that the brittleness you hear in brass fortissimo is not an artifact of the First Sound, but was there in the performance. I have heard it many times in non amplified live venues. Depending on the situation, cuivre is an artifact of sub-standard instruments or caused by performers with limited control, but is at times even artfully introduced as an intentional effect by extremely skilled performers.
If cuivre is not perceivable on other linestages, that may be more of a limitation of other designs than a flaw in First Sound.