VTL MB750 monoblock power amplifier
And there's always been a mystique about small amplifiers—that, even regardless of cost, you just can't make as good a big amp as you can a small one. Consider the great amps of the ages: the Audio Research D79B, the Mark Levinson ML-2, the tiny Bedinis, and, more recently, the sublime VAC 70/70 and the outrageous, break-the-bank Audio Notes. None of these were very powerful. Even the Krell KAS-100 was only a 100W design.
So the questions remain. Why the power? Just what will power do for you, and at what cost?
My first exposure to big-time power was, fittingly enough, the VTL Ichiban, direct ancestor of the MB-750 reviewed here. For years, I'd been looking for an amp that would bring the midrange/tweeter panels of my Infinity RS-1bs to life, with no success. Finally, my quest led to a guru who grinned and said, "RS-1bs? That's easy...any good 250W tube amp will do."
Serendipity being what it is, this occurred at precisely the time a local audiophile bought his second or third pair of OTL mono amps, and domestic harmony dictated that something had to go.
"You want to sell the Ichibans? Sure, I'll give them a listen, but I'll warn you up front—no way am I going to spend that kind of money on amplifiers."
A quick glance at the "Systems and Setups" sidebar will confirm that, yes, I actually did spend that kind of money on amplifiers. I did it gladly, happily, gratefully, and without a second thought. With the Ichibans in the system, the RS-1bs absolutely sprang to life. Two dimensions became three, black and white exploded into stunning Technicolor. I was most definitely not in Kansas anymore. The soundstage opened up, images had body, dynamic transients snapped the way they do in a concert hall or jazz club. I was mesmerized by the power. Since then I've heard any number of great little amps, but, gorgeous as they are, I always wonder how good they might be with four times the power.
If any company in high-end audio is hellbent on answering that question, it's VTL. As part of the company's re-engineering (see my interview with Luke Manley, "Making Tubes User-Friendly"), VTL has been steadily pushing the power envelope for tube amplifiers. The MB-750s are rated at 350W each in triode mode, a staggering 750 in tetrode. What's more, the 750s aren't even VTL's most powerful amplifier—that's the 1250W Wotan monoblock (footnote 1)...at least for now. At last January's WCES, VTL was driving a pair of Avalon Radians with four Wotans: 5000W of pure tube power. Call it excessive, but after we blew the hotel's breakers and powered the system back up with a single pair of Wotans, I swear that a bit of air was lost and the sound wasn't quite as effortless.
No, the 750s aren't the world's most powerful amplifiers, or even VTL's. But a pair of them, combined with my Ichibans and running the bi-amped Audio Artistry Dvoraks, totals around 2100W—probably enough power to tackle the questions posed here, as well as make for a toasty summer in Albuquerque.
Footnote 1: Reviewed by Jonathan Scull in the October 1996 Stereophile, with a "FollowUp" in June 1998.