Vacuum Tube Logic TL-7.5 Reference line preamplifier Brian Damkroger, December 2005
VTL's TL-7.5 Reference line preamplifier was designed by the same team, and around the same philosophy, as the S-400 Reference power amplifier, and from the beginning the two models were intended to be used together. Typically, when a design team creates matching products, much attention is paid to ensuring that their characteristics at least complement each other and, if possible, achieve a positive synergy. The Burmester 011 preamplifier (which I reviewed in the July 2005 issue) and Burmester 001 CD player are great examples of this: excellent alone, magical when used together.
But given that I had a hard time pinning any sort of sonic signature on the S-400, I couldn't help but wonder what that suggested about its companion preamp, the TL-7.5 Reference line stage—so I asked to borrow one and hear for myself. Because I had several CD players capable of driving the S-400 directly, I tried to isolate the 7.5's sound by switching it in and out of the signal chain, and by comparing it with the Burmester 011 and the Placette Remote Volume Control.
As with the S-400, I found it nearly impossible to ascribe any specific sound to the TL-7.5. Inserting it between an amplifier and a CD player—any CD player, even the Burmester 001—enlarged the scale of dynamic transients somewhat, and made microdynamics and inner detail much clearer, though not unnaturally so. My conclusion, after extended listening trials, was that the VTL was removing a slight dulling and veiling of the sound rather than artificially goosing it up. The same was true for other subtle aspects of the sound. With the TL-7.5 in the system, the soundstage was larger and airier, and both clarity and transparency were improved.
Comparing the VTL to the little Placette reduced the differences quite a bit, but they were still there, particularly the improvement in dynamics and image dimensionality and, to a lesser extent, inner detail. The Placette's transparency really impressed me when I first heard it; since then it's been a standard against which I've compared preamps and CD analog stages. Until the TL-7.5, nothing had come close, but the VTL really seemed to combine the best of both worlds: the Placette's neutrality and transparency with the ability to accurately reproduce dynamic transients from the smallest to the largest, and from the bottom to the top of the frequency spectrum.
Recalling that Paul Bolin had raved about VTL's TL-7.5 when he reviewed it in the October 2003 Stereophile, I pulled his piece up from the Stereophile website to see what, specifically, he'd had to say about it. I nearly fell out of my chair. Not only did his impressions and conclusions about the TL-7.5 mirror mine, they sounded eerily like what I'd heard from and written about the S-400 amplifier.
"It is no easy thing to attempt to describe the 'sound' of a component that had less intrinsic sonic character than anything else I have ever reviewed. The TL-7.5 had such an infinitesimal sound of its own, and did everything so supremely well, that I found nothing to rationally criticize. Sonically, it simply did not exist in the signal chain." Well done, Paul. I couldn't have said it better.
Having spent a year with VTL's S-400 and TL-7.5, my conclusion is that they are indeed a matched pair, but not because each synergistically complements the other's signature. Instead, VTL has effectively removed the colorations from both and lets the music—and the rest of the system, of course—speak for itself. Just as the S-400's $20,000 price is a lot to spend on a power amp, the TL-7.5's $13,500 tag is a lot to spend on a line stage—but I've heard nothing else like it. These are true benchmark products.—Brian Damkroger