Passive Preamps

Can't say I agree with all that is being said here based on my experiences.

I agree with Phaelon. Passives are a little to cool and the lack bloom of higher end actives.

Well isn't that the point to some extent? Just pass the signal, no colorations. If you want bloom by all means get a nice tube preamp.

I'm using two passive preamps right now with a third on the way. One is an autoformer volume control using the Slagle-man modules jointly designed by Dave Slagle and John Chapman. The other uses opto-coupler technology and was designed by an Aussie named George Stantscheff (Lightspeed attenuator). Opto-coupler technology is not new to audiophile components. Today Dartzeel uses it and Melos used it previously. Even Nelson Pass has published a schematic for a passive preamp using this technology. On another note you can buy a pair of Atma-sphere M-60 monoblocks with a passive volume control option that Ralph Karsten offers. I'd love to try that set-up sometime.

Shakeydeal has a point as well. Kevin Carter at K&K Audio built me a passive TVC using the S&B MkI transformers which in his opinion, and I concur, exhibited a nice touch of warmth.

All of these passives deliver dynamics in spades and a very nice sound stage in my system. In the case of the Lightspeed the purity of the signal being passed is mind boggling at times (all for $500). Passive preamps have replaced very nice active preamps such as a Joule Electra LA-100 MkIII and JRDG Capri in my system. Of course my front end components and amp have a say in this too, not to mention room set-up. A passive preamp in a passive friendly system can be a thing of beauty.

It is good to note that passives come in different flavors. I am not a technical expert in this, but a transformer volume control - TVC - I understand will generally work better and in more instances then just a resistive attenuated volume control in both impedance matching and for a fuller sound.

As I've said, with my TVC I don't lack any dynamics -- everything is as 'colorful' as it was with the few active pre's I've had, with the added benefit of more transparency and air between sounds. Bass is low and tight, highs are extended and detailed. Soundstage is better defined.

Another option is an active/passive pre in the same unit. Wyred 4 Sound, Placette and others make such pieces.

I second Tholt on the Promitheus TVCs. One more point I would like to add is that in case of TVC the amp's input sensitivity is VERY important. With a TVC, the input sensitivity of a power amp better be below 1.5V. With this n mind, there is absolutely no loss of dynamics or body or weight. The positives aspects with the addition of a TVC in your system are something to be heard and seen rather than describe in a thread.
So, system matching is very important.