Preamps - Active, passive...???

greatly improved dynamics from an active
better transparency from a passive
only you can decide which your own ears prefer

Bob, aren't dynamics a matter of impedance matching? (output, pre vs. input, power: ratio of 1:10 at least?)

learn a specification of your source components and power amplifier in terms of output voltage and input sensitivity/impedance first.

Some of the Cary amps as an example, have an input sensitivity of 9v, and there is no source component that I do know that can provide such an output voltage(up to 12V adjustable) to drive this kind of amp(s) without preamplification.

Almost all tube amps have impedance >=100kOhms and can be easily driven with passive preamp. SS can go as low as 10kOhms on the input; in this case you will not be able to setup a passive volume control for a sufficient amplitude bandwidth to control your volume with just attenuator.
But some SS-amp have input impedace >=50k which is sufficient enough to use with passive preamp.

Once you've jumped to the conclusion of having a passive preamp meaning that you've matched your source components and power amplifier, you'll need just to listen and compare. If you'll be dissapointed, there is nothing to worry about since most of the SS-output suorce components have a negative feedback applied to stabilize the output voltage which gives you a large lack of the dynamics(which is corrected by an active preamp). In this case the tubed output source components will be your best bet with passive preamps since tubes do not need an application of large negative feedback.

The source that I've grabbed this explaination is a)other audiogon forums, b)DIY experience c)listening experience. It is OK to ask a question(s) to get answers on New Today forums.

I've had passives for ~10 years now. I keep trying pre-amps from CJ, Krell, ARC, Levinson, and others. Some are nice but a well made passive in my system is more open AND more dynamic than ANY of the active units.

I've come to the conclusion that if an active line stage is required then there is something wrong with the system, typically the source component. Case in point : My Pioneer DV-05 with its wimpy power supply sounds better working into my MF X-Can v2 as a preamp than it does working into the passive. There is some loss of detail but the bass is better and presentation is punchier & more involving. However, my Muse 9 Sig definately sounds better working into the passive.

The source components need to have low(under~200 ohm)output impedances AND be able to source some current into say a 2K ohm load.

Not all passives are the same. I've had the Adcom line controller, Line Drive, Line Drive Deluxe, & TLC-1. However, my Reference Line Premminances 1 & 2 are the best by far. Full of bloom, detail and shocking dynamics (actually, they let all of that stuff thru without editorial change). They are cheap too (~$600-800 on the net)which makes them a low cost/risk try out. I'd love to try the Adcom GP750.

I've driven a passively bi-amped settup with over 6 meters of combined cable length with no problem. Just don't use funky cables with funky boxes & stuff and make sure your amp(s) has about 26 DB or more of gain.

Good Luck

I was on a search for a new preamp to replace a veiled and closed-in sounding Rotel RC995 and tried the CJ PV14 (tubie and slightly rolled off), Krell KRC-3 (dynamic yet slightly grainy and expensive), Linn Kollector (worse than the Rotel, wooly and fatiguing), Musical Fidelity A3cr (fairly transparent, a little bass bloom) and Levinson 380 (bright, grainy and expensive). Finally I tried the Placette Passive Line Stage and it was the only thing that didn't muck up the sound in some way. Some of the other preamps are quite good, like the MF A3cr, but all I was looking for was something that was sonically transparent (smooth extended highs, clean natural mids and deep powerful bass) to switch sources and change volume. This might not work in all setups, ie. 20ft interconnects to your amp, but if your ics are under 2m and your components can drive your amp louder than you'd ever listen, why not go with a quality passive?