VTL Siegfried Reference Series II Monoblock


Equipment report
Solid-state power amplifiers
VTL Siegfried Reference Series II
VTL Siegfried Reference Series II Monoblock

A few years ago a good friend took me to visit the office of Jon Platt, a top executive in the music industry who represents artists like Beyoncé and Jay-Z. It soon became clear that Big Jon, as he is known, is also a very serious audiophile, with a full rig in his home. In his office I got to hear the Wilson Alexandria X-2, Series 2 loudspeaker together with the VTL Siegfried amplifiers. It made a big impression upon me. Layer after layer, row after row of an orchestra or big band was revealed with rich, sumptuous clarity. I was truly impressed not only by the Wilsons, but also by the ease that the Siegfrieds displayed in controlling them. There was something magical about the synergy between the two. Big and powerful amplifiers can have a huge impact on the performance of even relatively efficient loudspeakers like the flagship Wilsons, and the Siegfrieds clearly did.

So it was with more than a pinch of interest that I followed VTL’s introduction of a new version of the Siegfried. When I first heard the Siegfried at the Rocky Mountain Audio Fest, it quickly became clear that VTL had upped its sonic game. I was eager to audition the amps in my own system. After TAS editor Robert Harley signed off on it and after I lugged the Siegfrieds down a flight of stairs with the aid of a chum, I was off to the races. And how! At about 800 watts of tube power in tetrode mode (at the push of a button it can also run in triode), the Siegfried is one of the more powerful amplifiers on the planet. It shows in ways both large and small. The Siegfried does nothing by half-measures. Quite the contrary. It is an amplifier with tremendous brio and swagger. Its scale is vast, its dynamics explosive, and its power reserves seemingly endless. Notes explode out of drums as though a shotgun had been fired. You will approach it with respect—its sheer size and weight bespeak seriousness of intent—and likely end up embracing it with fervor.

In Wagnerian mythology the boisterous Siegfried has to learn the meaning of fear, which he does when he alights upon a slumbering Brünnhilde. So this amplifier is aptly named; it may scare the dickens out of audiophiles who aren’t accustomed to listening to a grand piano sound almost as majestic as it does in real life or to the full three-dimensional, gut-wrenching bass of a rock ’n’ roll recording. Turn the volume up and the Siegfried will only get louder without any hint of compression. Your room will appear to be swelling with sound that wants to burst the confines of the walls. If I had to choose one word to describe the VTL Siegfried, then it would be grandeur.

The sheer oomph of the Siegfried really should come as no surprise because VTL has always specialized in what might be called the big bang theory of high-end audio. It wants that French horn in the back of the orchestra to come roaring out in all its lusty glory over the strings. The company was founded several decades ago by David Manley, then purchased from him by his son Luke. Now, together with his wife Bea Lam, Luke has taken VTL into a new era, one that leaves behind both the sonic and mechanical problems that often plagued tubed amplifiers, particularly ones that aspired to high power. The blunt fact is that high power and tubes have not always mated well together. When you pack twelve or twenty-four KT-88 or 6550 output tubes into an amplifier, then it isn’t a question of whether but when a tube will arc. Sad to say, but the quality of tubes nowadays is simply not what it was in days of yore, which is why the originals go for such a premium on the Web. The results—scorched boards, blown resistors and traces, and so on—could be most unpleasant for owners, who, more often than not, needed to be handy with a soldering iron.

With VTL’s deployment of microprocessors both for starting up and monitoring amps during use, those days are long over. Unless you are a glutton for punishment, you can only welcome VTL’s introduction of a measure of comfort into the listening experience. No longer will you have to sit listening with a wary eye on a bank of tubes that could explode at just about any moment. Instead, most of VTL’s amplifiers incorporate a fault-sensing system that can detect if a tube is about to blow and shut it down before it can do any damage. (A small LED will blink next to the tube to indicate the troublemaker that needs to be replaced.) The Siegfried contains a host of other features that make it a user-friendly piece of equipment, including a front display panel that counts the numbers of hours that the tubes have been playing—about 2000 hours is a good time to change them.

At the heart of the Siegfried—and what truly sets it off from its competitors—is its precision regulated power supply. The power supply ensures that the tubes keep their correct bias— no more fiddling to set it by the owner. It’s done for you. At the same time, Siegfried regulates the power supply to avoid the voltage sag that typically accompanies dynamically demanding passages as the amplifier draws upon the power supply.

Since a number of these features were also present in the Series I version of the Siegfried, which I reviewed for TAS several years ago, what’s the big deal about the new one? Why the fresh designation?

For one thing, it boasts a fully balanced audio circuit that uses 12BH7 driver tubes instead of the 6350s in the previous version, no global negative feedback, new output transformers, Mundorf silver/oil capacitors, and four settings—low, medium, high, and max—to allow users to adjust the output impedance of the amplifier, depending on how much damping you feel needs to be applied to the woofer in your speaker. I used the medium setting. The balanced circuit clearly seems to have lowered the noise floor. I found that the fully balanced VTL 7.5 Series III preamplifier drove it in exemplary fashion, and Transparent Audio was kind enough to send me both a balanced interconnect and an extra set of Opus MM2 loudspeaker cables (here I should also note that Transparent sent two hefty 20-amp power cords that substantially boosted the performance of the Siegfrieds). I have found the Opus cables transmit a sense of dimensionality I have not yet heard another cable supply. In this case, they seemed to mate beautifully with the Siegfried and Wilson XLF. It is not essential to run the Siegfried with a balanced preamp—it will convert the signal at the input—and I found that the non-balanced Ypsilon PST-100 Mk. II upped dynamics another notch.