VTL’s New Siegfried 800 Watt Reference Monoblock Amplifier Features ‘Tube-Smart’ Self-Adjusting Technology

The new all-tube monoblock reference amp from VTL (Vacuum Tube Logic), first shown last month at the Home Entertainment 2003 show in San Francisco, is designed to make high-end tube amplification easier to use, through self-adjusting technology that optimizes performance automatically.

The new Siegfried 800 Watt Reference Monoblock Amplifier incroporates “tube-smart” technology that VTL’s engineering team has been developing over the past five years. It provides continuous real-time feedback of important performance parameters and automatically self-adjusts to maintain optimum settings, using software control to dramatically extend tube life.

VTL says that sound quality has also been taken to a new level with increased dynamics, more realistic instrumental timbres, and a harmonic richness nearer to live music.

“With our new ‘smart’ amplifier, we have truly put technology in the service of music,” says VTL president Luke Manley. “With all of the guesswork removed from the amplifiers’ operation, the user can simply sit back, relax, and enjoy the music.”

The Siegfried has been under development since 1996, when VTL introduced its previous reference model, the 1250 Watt Wotan amplifier. At the time, VTL described the Wotan as “the culmination of all we know about amplifier building at VTL.” But even then, the company recognized that the growth of home theater meant that amplifiers were being called on to perform an array of new functions in the home, and that VTL’s tube equipment would need to change to fit into modern home entertainment systems.

VTL identified reliability and consistency of tubed components as key issues that had to be addressed.

Luke Manley and VTL set these design goals for the new reference model:

  • It should deliver a new sonic standard, unsurpassed sound quality as well as excellent measurements on the test bench
  • The amplifier must be able to drive a wide range of speaker types to their optimal performance, with consistent performance under all conditions
  • The amplifier must be self-optimizing and provide a full range of diagnostics for sustaining peak performance
  • The operation of the amplifier must be intuitive and user-friendly while providing flexibility in its control functions, for integration with modern home theater systems

“The R&D process ended up being an intensive cross-disciplinary collaboration between multiple teams of engineers in different parts of the country,” says Luke Manley. “Tube circuit designers, power supply experts, software engineers, control circuit experts, and industrial design specialists all had a hand in shaping Siegfried.”

The quest to make Siegfried “smart” was a major part of the design process. VTL was committed to eliminating the continual tweaking and guesswork that usually come with owning large tube amplifiers. Automatic self-regulation was understood to be the key to keeping Siegfried operating at peak performance.

To that end, engineers embedded a logic-controlled automatic tube biasing circuit inside the amplifier to ensure that Siegfried is running optimally at all times. A full range of diagnostic functions were also included to let users know which tubes need to be changed, amplifier operating time, tube life, real-time AC voltage and more.

Siegfried’s sound quality took a significant leap forward, due in part to the use of new precision-regulated power supplies. Benefits of the new design include increased dynamic headroom and a tighter, more tuneful bass. A balanced input stage keeps the noise floor vanishingly low.

Siegfried’s physical package has been given special attention in the design process. The thick and extremely rigid chassis (provided in a tower configuration) is clad in non-magnetic material and rests on large non-resonant feet to banish mechanical interference.

The sleek, modern appearance of Siegfried matches the cosmetics of VTL’s TL7.5 Reference Preamplifier. A curved fascia is inset with a digital readout and three buttons.

“I couldn’t be more pleased with the way our new ‘smart’ amplifier has turned out,” says Luke Manley. “Siegfried has surpassed everyone’s expectations with respect to sound quality and ease of use. This is an amplifier you can turn on and forget about. Just sit back, relax and enjoy the music.”

VTL Web Site

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