Do all Passive preamps exhibit this trait

One other thought, try the new Pass B1 unity gain buffer preamp. The buffer eliminates the impedance issues and the circuit does not have a gain stage. Sounded really good at RMAF when I heard it there.

If you don't want to pay the Pass dollars Audiogon member Rawsonte has been advertising a couple DIY versions here for great prices.

Maybe that "more extension and detail" you experience with this pre-amp is exactly what makes it fatiguing and is not representative of what an high quality active pre-amp does when it does highs right. For me, highs done right, is like a star against a night sky. The sky is darker, the star stands out more sharply BUT is not, in itself, brighter. Does that make any sense to you?

In my experience with other units v passives the biggest difference can be in dynamics. As mentioned set up of a passive to compensate for IC impedence problems, etc, can make a big difference.

IMHO, you just need a better (not necessarily more expense) active pre-amp. Oh, BTW, if you decide to go with a passive be sure to do lots of research 1st. They are NOT all neutral, some are additive or subtractive.

I have been using a Reference Line Preeminance 1A passive preamp for the last two years. I find that recessed treble and listener fatigue comes primarily from poor recordings.

The passive to my ears lets everything through as recorded. It has meant that some CD's sit on the shelf because the recording values suck.

I am using the Adcom gfp-750 with two Classe Dr-15 amps (in bridged mode), Apogee Stage speakers, Marantz SA-1 SACD Player, Krell 300cd player, Herron MM phono stage with VPI Scoutmaster turntable. Cables have been Cardas Golden Reference (very low capacitance) and Nordost Quattro Fil. I've switched between both cables and haven't noticed much difference as it relates to treble extension. There was an online magazine review done which noticed the lack of transient decay when the Adcom was used passively. I suspect that's it's a feature of this preamp which can't be overcome regardless of which cables and components are used. Can anybody confirm this or had a similar complaint with the GFP-750?

I alternate between passive and active preamps and find that the difference is that usually described, active better dynamics, passive more transparency less coloration. But with good equipment the differences are not earthshaking. I am not absolutely positive that I could pass a blind test as to which was playing if I didn't have the other to compare. But one thing is clear, passive gives you more bang for the buck. In Martin Colloms testing the Creek 21 and 22 placed ahead or a lot of Krell, Audio Research, Conrad Johnson, etc active preamps. All this is contingent on your CD player having an output stage that will drive a power amp and a power amp with reasonable input sensitivity. My Meridian 605s only need .5 volts.