I don't see the point of tube preamps. Since they don't amplify anything, the primary benefits of using tubes (i.e. preserving the nuances of the signal during the gain stage) are not realized, and what you DO GET is tube hiss added to the low level signals (inside the preamp) which go on to be amplified. (BTW, tube amps, if they are even halfway decent don't produce audible hiss.) So, in my ever so humble opinion, the only place for tubes is in devices that amplify: power amps, mic amps, and phono amps; and certain miscellaneous pro gear. Don't argue with me, my mind is made up!
All that said, about two years ago, due to a series of very unusual and sad events (the death of an audiophile friend), I had the opportunity to listen to an Atma-Sphere MP-3 preamp in my system. I wouldn't have bothered, really, but I couldn't let it out of my hands without hearing the MP-3 preamp's phonostage. As someone mentioned earlier, Ralph doesn't make a standalone phonoamp. And the phonostage in the MP-3 represented my "dream" phonostage, which is:
1. Fully balanced differential circuit (best with MC cartridges which are balanced output devices to begin with.)
2. All tube gain stages from input to output! No FET's or SUT's! And unless your MC cartridge is "old technology" and has an output below .4 mV, you shouldn't need those "crutches" anyway. At .4mV cartridge output and above, there will be enough gain to keep any hiss to a minimum -- especially if you're willing to spring for the strongest 12AT7's on the planet -- the GEC A2900 ;~)
3. Believe me, I'd been searching for such a phonoamp for a long long time (but not thinking to look for one buried in a preamp!) and I never found one designed like the phonostage in the MP-3 (as well as in the more expensive MP-1).
So I removed my Levinson 26S preamp and 25S phonoamp from the system, and inserted the MP-3. Things were never the same! I use a Transfiguration Temper W (same as Ralph ;~) and at right around .6mV there was just a little hiss, but only with phono source, and cranked up pretty high. The linestage in the MP-3 is also extremely quiet for a tube preamp (no doubt because it also uses fully balanced differential circuits.)
The Levinson gear is gone. To Singapore, and at a profit well over what I paid for it 10 years ago! The MP-3 went back to Ralph for (most of) the upgrades, and to have him add two more pairs of balanced outputs (one pair isn't enough for most applications, in my opinion.) I really love this preamp and feel it equals many others at three times the price, that don't do (for me) what it does.
I only have one issue with the MP-3 (not a "problem", just an "issue" ;~) and it's the fact that the phonostage (in which I use 3 pairs of very expensive tubes,) is always ON, even when listening to other sources! I've begged and pleaded, but Ralph doesn't seem inclined to make a standalone phonoamp. I even know one person (an audio manufacturer) who only uses his MP-3 for playing vinyl! Must be nice . . . .
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