Passive preamp for Tube Amp?


Has anyone tried using a passive pre with a tube amplifier? In particular I am interested in a passive like a Placette PVC with a McIntosh MC275. Primary source will be phono via a Rogue Stealth. Speakers are Quad 2805.

I have heard mixed reviews on whether this would result in softened dynamics and bass impact. Many of the published reviews of the Placette are very positive, but I have read some posts by actual users who mentioned the softened dynamics and weak bass.

The Placette comes with a 30 day home trial, but I am just looking for as much information up front as I can get. Thanks for any wisdom here...

Dave
tricon_dave
If your willing, check out the Sonic Euphoria PLC. It has been reviewed by Stereophile and they felt that the did not have trouble with Bass and Dynamics. Jeff Hagler's design using an autoformer eliminates the Bass and Dynamics issue. I have one that I use from time to time and IMHO it would be worth checking out. Good Luck
I've used an EVS stepped attenuator with McIntosh MC30's driving Maggie SMG/A's and loved them. Not a 'rocking' setup, but for anything short of metal it was a great sound and I never had any trouble getting plenty of level from it despite being passive.

The Maggies are softer and lighter in the bass than most box speakers, so it might be a bit apples and oranges, but I'd give it a try if the home trial is available.
Dave,
Passives are a wonderful transparent big soundstage way to go.
You need to be aware of your output impedence of your CD player and your input impedence of your amp. I have owned and listened to many passives.
Interconnect length is a big deal, as short as possible. My personal favorites are from Reference Line, the Placette is a good one also, for the money.
Try it, you might like it. I use a new version of the Reference Line Preeminence One with a VK60, and have great bass, and a clean, clear, transparent soundstage that goes on forever that a active can never provide.
I use two Placette Preamps so I've had lots of experience with them. The idea that Placettes soften dynamics and weaken the bass punch is pure nonsense. Placette's pass All of the sound through completely undistorted using Vishay resistors with an accuracy of +/- .005%. No other passive line control even comes close. The only problem with the Placette passive line contol is that it, as the name implies, has no amplification for phono sources. The Placette Active Preamp must be used in this case.
Consider the following:

Using a passive attenuation device requires that you optimise electrical "energy transfer" parametres (between pre & amp)

1) The output impedance of the pre and the input of the amp are important. The placette seems to have a reasonably low output imp and reasonably steady across the audible spectrum -- and this helps.

2) The source component (i.e. whatever precedes the "passive" pre) will be driving: wire-> volume control (passive pre)->wire->amp. So it must have a strong output.

3) Softened bass is usually the sign that insufficient energy is entering the amp -- it has to do with the source, the impedances of the amp & the attenuation device (passive pre).

4) If you know the input impedance of yr amp & the output specs of the Rogue, you can guess what the results would be. Or, you can try it.
Try a TVC, especially those that use S&B transformers like the Bent or K&K (which is the one I have). I've been using one with a 2V digital source, a phono stage with 64db of gain, and an amp with 67K input impedance. Amazing transparency, clarity, and soundstage. With a TVC you still need to pay attention to impedance matching, especially with the sources driving the TVC, but you have more flexibility than what most resistor based passives can offer.

Here is an interesting link that will help explain the impedance of a TVC:

http://www.stevens-billington.co.uk/page102.htm
Placette Active does not address the issue of gain for phono - it has no gain, only sophisticated buffering.
Hi Dave, I have a beautiful original McIntosh Mc 275 that I am using with my Placette Passive 3 input preamp. Speakers are 1989 Klipschorns and the sound is spectacular. Believe me there is no loss in dynamics, not with this combination. Placette is great in that it passes through the sound of the amplifier just about as uncolored as anything can. It does this so well that I can clearly hear the differences when I change any of the tubes in the McIntosh. I now listen to my Oracle Delphi turntable and just sit back and enjoy. Happy Listening, Tony Nicosia
I agree the RVC is extremely fast, uncolored and transparent, but if you compare it Placette Active (I owned both) you will notice something was missing in the bass and midbass - the difference was very obvious to me and I would say my set-up is very "passive" friendly. The SB102 based TVC (S&B xfromers) I just got is also extremely transparent, quiet, etc, but I beleive it has significantly better bass than the RVC has and a touch of warmth, that most users will like very much IMHO. This does not mean the RVC is not excellent, it is, and you will be fine with it, but when you start comparing it with either the Active version or the good TVCs, I think you might make a different decision as to which you prefer.
I have yet to hear the Placette Active, although I would love to arrange an audition one day. As for the Placette Passive I find it works just fine for getting bass and midbass out of my vinyl through a Whest Phonostage.20 + MsU.20 phono preamplifier. But then again as I have said I have not yet heard what the Active version would do.
I am in a 30-day free trial using the Placette PVC with a Conrad Johnson MV60 tube amp. Sound is excellent, wonderful imaging. I am waiting for a CJ preamp to arrive so I can compare the two and make a decision during my trial period. With a 30-day trial, you have time to make comparisons in your home. If you buy the other preamps right, and decide to keep the Placette, resell them near the same price you paid.
Another excellent use for the RVC is to use it in line with your pre to give you 100s of volume level combinations, expecially when you have a stepped attenuator or a pre/amp combo with too much gain (e.g., CAT SL1) - a truly transparent device (which of course does not mean you enjoy listening to it as much as something else, even if not quite as transparent and uncolored).