I got lucky years ago, and got my hands on a First Sound Reference Passive preamplifier, straight from Emmanuel Go. I went for the model without the bling-y (such a word didn't exist back then) gold knobs. Vishay resistors, point-to-point silver wiring, copper chassis, full dual-mono, the whole magilla.
Back then I was also reviewing audio gear, and preamp after preamp after preamp came through the house, and none were anything close to it in terms of just letting the music do what it does. Not sure if that is still true, nor do I fancy delving into preamplifier madness when I already have a lovely one.
I have heard other passive pres sound thin and kinda bassless. The First Sound was, at the time (20 years ago) the only passive I heard that could slug it out with the big boys. I reckon that's still the case, but at the time the problem was "HOW much for a passive preamp?!"
Not sure why passive preamps have gotten such a bad rap, except that they are not for every system. I run mine with PS Audio 250 Delta monos, and have nothing but sonic joy. There are limitations, however, not least of which is that your front end has to kick butt and take names, quality-wise. Or you will hear it, and it will suck.
I also ran into (back in the day) gain problems with phono stages. The guy who built my Analog Research Legato was able to account for the passive pre, and everything rocked. I'm now using a Grado phono stage, and for "normal" listening levels (in quotes because it's such a variable level), I am running the volume knobs at about 2 o'clock.
But here's an excerpt from a review I found of one of his active preamps that explains a little behind the First Sound philosophy with the Reference passive:
"Those who do know Go, most likely heard of him initially back in the late 80s or early 90s when he launched the lavishly titled and extremely well received First Sound Reference Quality Passive Preamplifier. A purely passive product, it offered unmatched levels of clarity, detail retrieval and dynamics. Well, dynamics if the match between source and power amplifier were correct. It also rendered wonderful, complex and full harmonic texture again if the source and power amplifier cooperated. And therein lie the problem that Gos passive preamplifier faced, one it shares with every passive correctly matching source and power amplifier."
The reviewer-described sonic qualities (as well as complexities) are all true. It's why I ultimately decided to keep my PS Audio amplifiers, because they work so well with the passive pre.
Good luck in the quest, and if you can get the setup right you will, as Waynec and others have found, some full-on delight.
What I can't figure out, and perhaps someone here can, is why passives seem to like amps with a LOT of power. I heard the First Sound at a CES connected to some of the (then) 4-chassis Atma-Sphere KT88 amps. They were driving Sound Lab A1s. It was the best sound that I had ever heard (and still is). I couldn't afford the amps or speakers, but I could (just) swing the passive pre. I grabbed it, and have never looked back.
Perhaps there's one lurking out there in used equipment land, as another option for you to consider. Again, good luck in the quest.