The story continues...
I was now ready for my first listening session, and more than a bit nervous to hear the result. Here I was, with a new preamp that has already been modded, new tubes (which always sound veiled to me) and recollections of other tube gear, most of which added significant warmth, rounded off the edges, damped the dynamics, and always, always (with the exception of the Capitole) added significant noise. I hate tube rush and hum -- maybe because I don't have my sense of sight I am more sensitive to it than most (which is in no way meant to imply that I hear any better -- my brain just pays more attention to auditory information than the average person), and of course there is the problem of tube "bloat" in the midrange. I love the dimensionality of good tube gear and the harmonic body and textures that a good SET can reveal and present in a very palpable way -- the wood of a guitar or cello, the head of a drum and it's trailing resonances, and so on.
Ok, everything is warmed up, a small stack of CDs from several genres and that I'm intimately familiar with sitting next to the Denon, and I'm ready to begin...
Hmmm, no sound -- Ah, you have to select the correct input, idiot!
Ok, now over to the listening position and start the first CD. It took an eternity for it to start and then... all I can say is WOW!
So, what was there? Well, let's see, there was the full force of the music, all the extension and dynamics intact, more of that "harmonic body" across the spectrum, and a soundstage that was at least 30% larger with great imaging. The presentation was a bit forward compared to the original passive setup, but I figured that to be the stock tubes, or at least something some tube rolling could take care of. I'm not worried. There was one more thing that was there which I was not expecting at all -- more, yes, more, detail -- something which I was thinking was going to be lost to some degree with the tube pre. When I can hear background singers taking breaths between phrases, I know it's good.
So, what wasn't there? Noise. Noise wasn't there and that stunned me. I had become very accustomed to the black background of battery powered tripath amps having used them for the last year or so. I like the spaces between notes to be silent now (when they're supposed to be), I like hearing reverberations decay to nothingness naturally, and so on. This was one of my top priorities for a tube preamp and this certainly didn't disappoint. Ok, that out of the way, it was on to the next thing -- detail, and as I have said, there appears to be evenn more detail with the preamp in the system I'm guessing that this has to do with impedance matching in an all-passive system versus the system with an active drive stage -- in fact, I attribute much of what I'm now hearing to that phenomenon. Dynamics? There is spades -- no worries here, and again, leading edges seemed even sharper when they were supposed to be -- not like any tube gear I've ever heard.
Now for the million dollar question: was the tone or harmonic body there in that way that I so enjoyed with a single-driver SET amp? A resounding "yes"! drums now sounded like drums with drum heads and body resonances instead of percussive thwacks. On Jerry Garcia and David Grisman's Shady Grove CD, Jerry's guitar has a very real woody tone now and Grisman's mando not only sounds like a mando, but a classic Gibson mando. Across the board, at all ends of the spectrum from cymbals and mute trumpet to ddouble bass and tympany, it was all there and all good. Not artificially bloated in the mids, with no discernable noise, and all the dynamics anybody could want plus something else... that one last thing... that quality of dimensionality that only tubes can bring. I had found it and it was good.
I took out the stock tubes and rolled in a NOS military grade 1950s Genalex (made by Mullard) rectifier, a rrarely used but highly musical 12FQ7 in the buffer stage (which can only be done if you have had the modifications done), and a brand spanking new 1955 CBS/Hytron 8514e (12au7 equivalent) in the gain stage. When I first listened to this combination it sounded slow and muddy and very dark. I had heard the hytrons sounded closed in and slow for a while but much better after a day or two of play, and sure enough, a couple of days with this holy trinity of tubes in the preamp I had finally arrived.
Now, should this sound like a raving review of the modded Minimax preamp, well, it sort of is, but the real point of all this is that without an amplifier that can do absolutely everything the source signal demands of it, the best sources and preamps in the world won't get you any further than the amp will let you go, and the Signature 70s deliver! They deliver it all, with no strain, no hint of holding back, and no sign that anything can push them to the breaking point (of course every amp has it's limitss and common sense should be exercised), and all this without a hint of hum, hiss, or any other nasties to ruin the effects.
I now know that the Signature 70s are going nowhere, nor will be the little giant of a preamp, and even though I now know that the sound I'm experiencing is the best that I've ever had, it's only going to get better with improved sources, power delivery and perhaps that Response Audio EXtreme makeover for my Adagios. Now I'm confident that I can hear any subtle changes anywhere in the system, and that has not always been the case.
Looking back, I really am at a loss to explain this, but as I mentioned earlier, the only thing that makes any sense at this point is some sort of impedance mismatch, non-linear reactive losses in the signal path from the source to the speakers, etc., but whatever it was, when the drive of a tube preamp that is apparently adding no perceptible noise, preserving detail and dynamics, and adding a dimensional richness was introduced in the system, it really showed off everything the Signature 70s are capable of -- which is a faithful representation of the sum of the upstream components feeding it, and in my case an 89dB, 2-way transmission line speaker as the load.
So, 4 weeks ago I was seriously pondering selling my Signature 70s, and now you'd have to pry them from my dead body if you want them, and all because a small, affordable, capable preamp was able to deliver what the amps have been wanting all along.
Do I need to say that this is my ears, my tastes, my room, my speakers, etc., and that YMMV, but I am now firmly in that growing camp of believers who think the pairing of a good tube front end with digital amplification is as close to audio heaven that I'm going to get.
Vinnie, thanks for hanging in there with me, ! When it comes to my music, I'm generally a pretty hard customer to please, but given my financial limitations I'm driven to find the most for my money that I can possibly afford, and now I don't know that even if I had all the money that one could want, that I would change this setup -- it does everything I need, and does it beautifully.
Best,
Jim
