Lohengrin Reference

Since the launch of Siegfried Reference monoblock and S-400 Reference stereo amplifiers, VTL has earned worldwide acclaim for its reliable, high-power, and high-performance amplifiers, celebrated for both their musicality and ease of use. As the first tube amplifiers to incorporate true automatic bias and fault-sensing technologies alongside precision-regulated power supplies, VTL Reference series has won the favor and affection of audiophiles around the globe.

With the launch of the Lohengrin Reference monoblock amplifier, VTL has pushed the boundaries of high-power tube amplification to new heights. The Lohengrin is not merely a new amplifier; it embodies VTL’s unwavering passion for audio excellence, setting a new benchmark for musicality and sonic authenticity. The result of five years of dedicated research and meticulous refinement, the Lohengrin encapsulates the wealth of knowledge and deep understanding VTL has cultivated in the pursuit of lifelike music reproduction. We have remained steadfast in our vision to create an amplifier that illuminates the essence of the music, bringing listeners closer to the artist’s original creative intent.

VTL power amplifiers are renowned for a modern sonic signature that combines robust power, rich harmonics, and intuitive ease of use; they have long been acclaimed for delivering the speed, delicacy, and musical agility typically associated only with low-power amplifiers. The Lohengrin, however, elevates these often elusive qualities to a whole new level.

Lohengrin amplifier employs an eight-tube output stage configuration delivering 400 watts of power, while incorporating the driver stage and power supply sections from the more powerful Siegfried amplifier. Compared to solid-state designs, vacuum tubes are easier to drive and avoid the “current overload” issues often associated with parallel configurations, allowing the Lohengrin to achieve an ideal balance between power and responsiveness. Its innovative technology lowers output impedance, reduces the step-down ratio required for the speaker load, and enables the use of a simpler, more efficient output transformer.

Our precision regulated power supply ensures that the output tubes operate at their optimal bias point, even under heavy loads. We employ a wide-bandwidth, multi-section interleaved output transformer to guarantee smooth, grain-free high-frequency extension. The Lohengrin features a zero-global-negative-feedback design, wide audio bandwidth (-1dB at 100kHz), and an adjustable damping factor, allowing for flexible tuning based on speaker load and listener preference.

Amplifier’s user interface makes tube operation intuitive and hassle-free. Fully automatic bias control and a comprehensive, multi-layer fault detection system enhance reliability and simplify output tube management. A full two-way RS-232 interface provides control and diagnostic information.

Musically, the Lohengrin offers a seamless transition across the frequency spectrum and a precise, expansive soundstage, recreating the atmosphere of a live performance with astonishing realism. It keenly captures micro-dynamics—those subtle shifts in intensity that musicians use to convey beauty and emotion. Low-frequency instruments are rendered with a linear, clear, and controlled character. True to its heritage, the Lohengrin elegantly yet powerfully conveys the gravitas and authority of the original performance. The sound is fresh, vibrant, and deeply immersive, drawing the listener right into the heart of the music.

Built upon its signature dynamic expressiveness and authoritative sound, Lohengrin delivers an extraordinary sense of immediacy that draws the listener deep within—transcending mere sonic accuracy to reach something more subtle and authentic: the hidden intentions, elusive emotions, and unspoken truths that the musicians strive to convey.
Utilizes fully balanced differential input and driver stages to enhance signal swing, bandwidth, and stability.
Fully balanced differential circuitry—generating balanced signals from single-ended outputs
Zero global negative feedback
Shorter, faster feedback loops enabling superior tonal control without phase shift.
It handles speaker loads more easily, thereby improving signal stability.
This amplifier offers absolute stability and requires no capacitive compensation.
Low-impedance output stage delivering superior speaker control.
VTL’s proprietary balanced reference output transformers significantly enhance interleaving and coupling, resulting in wider bandwidth and zero ringing.
User-adjustable DF feedback control allows for adjustments to output impedance and damping factor to achieve optimal matching with speaker load.
Precision-controlled supply of printing plates and screens
Software microprocessor control
Switchable tetrode/triode mode
Automatic offset, fault detection
Inrush current limiting
Standby mute function; reduces tube current to extend tube life
Full bidirectional RS-232 control
400 watts per channel in tetrode mode; 200 watts per channel in triode mode
Each monoblock module utilizes eight 6550 or KT-88 vacuum tubes.
Adjustable, precision-regulated power supplies for the plate and output stage ensure stable operating points for the output tubes; independent regulated power supplies for the input and driver stages enhance signal resolution and tonal quality.
Adjustable, precision-regulated bias power supply enhances signal resolution and noise rejection while improving isolation from mains voltage fluctuations; the operating point of the output tubes remains unaffected by normal AC power variations.
It employs a microprocessor-controlled automatic bias system and multi-layer redundant comprehensive fault detection to protect the amplifier from output tube failures.
All capacitors in the signal path are premium Mundorf silver-in-oil types.
Film bypass capacitors are used across the power supply capacitors to achieve superior high-frequency resolution.
Extruded aluminum alloy front panel features a luxurious, modern design, with a viewing window that allows the internal piping to be seen. Available in black or silver finishes.
Sturdy structure, improved ventilation, and lower operating temperatures.
Vacuum Tube Complement
1 x 12AT7, 2 x 12BH7, 8 x 6550 or KT-88
Output Power 20 Hz – 20 kHz, into 5 ohm load
Tetrode 400W, Triode 200W
T.H.D. 20 Hz – 20 kHz @ 400W Tetrode
< 2.5%
T.H.D. 20 Hz – 20 kHz @ 200W Triode
< 2.5%
Inputs
Balanced XLR (1), Single ended RCA (1)
Output
5-way Binding Post (1 pair)
Class of output operation
AB1
Optimal Load Range
4 – 8 ohms
Input sensitivity
Variable between 1-2V, depending upon DF setting
Input impedance
47K Ohms
Balanced Input Common Mode Rejection Ratio
60 dB
S/N Ratio @ 400W Tetrode
S/N Ratio @ 200W Triode
-110dB, 120 Hz
Power consumption
Idle: 350 W, Full Power: 900 W
Secondary DC Fuse Ratings
Plate: 4A Fast 600V, Screen: 0.75A Fast 600V
Primary AC Fuse ratings
Logic: 1 Amp Slo Blo 120V, 220V, 240V
B+: 120V: 15 Amp Slo Blo, 240V: 8 Amp Slo Blo
Input: 120V: 2 Amp Slo Blo, 240V: 1 Amp Slo Blo
Filament: 120V: 2 Amp Slo Blo, 240V: 1 Amp Slo Blo
Dimensions W x D x H
11.5″W x 19.25″D x 19.5″H (29 x 49 x 50 cm)
Unit Weight
Net: 170 lbs / 77 kg each unit
Shipping Weight
500 lbs/227 Kg (both units packed in one crate)