Twelve 6550-type output tubes per channel drive this build to a rare 650 watts in tetrode mode, and each monoblock weighs 90kg on its own, 180kg for the stereo pair, before it even reaches the loudspeaker. This is the VTL Siegfried Series II Reference, a veteran of the high-power tube amplifier market, paired here with the Wilson Audio Alexx V for a room Hifiverse rated specifically for bass that "remains clear even at high volume, without buzzing and distortion."
The system at a glance
Two components, a massive American tube amplifier pairing with Wilson Audio's second-largest current flagship, together representing one of the more unusual high-power tube-versus-demanding-speaker combinations shown at Munich 2025. This is a system for a listener drawn to VTL's reputation for challenging the assumption that vacuum-tube amplifiers are inherently power-limited, applied here to a loudspeaker whose low-impedance dips have historically demanded genuine current from whatever drives it.
Why these components work together
The Alexx V weighs over 200kg per side across four separate enclosures, its bass module carrying 26cm and 31cm woofers in an open skeleton mount that lets the upper modules be horizontally repositioned relative to the bass section to synchronise timing between them. That kind of adjustable, multi-module engineering rewards an amplifier with genuine reserve capacity, and the Siegfried Series II Reference is built for that role - huge stabilised power supplies, the source of the amplifier's substantial 90kg-per-chassis weight, deliver up to 650 watts per channel in tetrode operating mode from its twelve-tube array, a power figure that puts serious tube amplification within reach of a loudspeaker load many owners would instinctively pair with solid-state amplification instead. VTL's own reputation as a "veteran of the high-power tube amplifier market" rests on this ability to deliver substantial current from vacuum-tube topology rather than accepting the modest wattage figures most tube designs are limited to, precisely the capability the Alexx V's demanding low-impedance dips require to sound controlled rather than compressed.
How it sounds
Hifiverse's own Munich verdict, bass reproduction that stays clear at high volume "without buzzing and distortion," reflects exactly what a high-power tube amplifier paired with a loudspeaker built for adjustable time alignment should deliver - the Siegfried's substantial current reserves keep the Alexx V's woofers under control even when driven hard, avoiding the compression or breakup lower-power tube designs would introduce against this particular loudspeaker's demanding load.
2 components
- Floorstanding loudspeakers
Alexx V
by Wilson Audio
Wilson Audio Alexx V - floorstanding loudspeaker. One Alexx V speaker weighs more than 200 kg and consists of four housings. The base is a bass module with two drivers with a diameter of 26 and 31 cm. It has a system of three boxes mounted in an open "skeleton" mount on two side brackets. It allows you to synchronize the sound of the modules by changing their horizontal displacement.
- Power amplifiers mono
Siegfried Series II Reference
by VTL
The veteran of the high-power tube amplifier market outputs up to 650 watts of power in tetrode mode, with 12 6550 type lamps used in each channel. Huge stabilized power supplies and an impressive case are responsible for the impressive weight of 90 kilograms per monoblock or 180 kg for a stereo system.