Lohengrin Reference Monoblock

Lohengrin

Since the introduction of the Siegfried Reference monoblock and the S-400 Reference Stereo amplifiers, VTL has been widely recognized as the leader in the world of reliable, high powered, high performance amplifiers, both for musicality and ease of use. Known as the first tube amplifier to deploy true Auto Bias and Fault Sensing, as well as precision-regulated power supply technology, our Reference amplifiers have won the loyalty and appreciation of serious music lovers around the world.

With the introduction of the Lohengrin Reference monoblock amplifier, VTL is pushing the boundaries of high power tube amplification to a new frontier. Lohengrin is more than just a new amplifier; it demonstrates VTL’s ongoing commitment and passion for audio excellence, establishing a new benchmark for musicality and sonic realism. Developed through five years of dedicated research and refinement, Lohengrin embodies VTL’s extensive accumulation of knowledge and deep understanding of the technologies essential to lifelike, realistic music reproduction. Our guiding passion is to craft an amplifier that illuminates the music, drawing listeners closer to the essence of the artist’s intention.

Renowned for modern-sounding designs that balance formidable power with harmonic opulence and intuitive ease of use, VTL amplifiers have long been celebrated for their ability to deliver speed, finesse, and musical agility typically associated with lower-powered amplifiers. With Lohengrin, these often-elusive qualities are elevated a new level.

The Lohengrin amplifier features an eight-tube output stage configuration capable of delivering 400 watts, retaining the higher-powered Siegfried amplifier’s driver stages and power supply. By employing tubes—easier to drive than transistors and free from the “current hogging” issues common in parallel designs—the Lohengrin amplifier achieves an ideal balance of power and responsiveness. Its innovative technologies produce a lower output impedance, reducing the necessary step-down to the loudspeaker load and enabling a simpler, more effective output transformer.

Our Precision-regulated power supplies hold the output tubes at optimal operating points even under demanding loads. Our wide-bandwidth, heavily interleaved multi-section output transformers ensure seamless, grain-free extension into the upper frequencies. Lohengrin’s zero global negative feedback design, broad audio bandwidth (-1dB at 100kHz), and adjustable damping factor provide capability and flexibility for tailoring to the speaker load and listener’s preference.

The amplifier’s user interface makes tube operation intuitive and worry-free. Fully automatic bias control and comprehensive, multi-layered fault-sensing systems enhance reliability and simplify the management of the output tubes. Fully bi-directional RS-232 interface provides control and diagnostic information.

Musically, the tonal spectrum of the Lohengrin is seamlessly integrated from top to bottom, the soundstage is precise and expansive, revealing the venue where the musicians perform with astonishing realism. Lohengrin reveals micro dynamics – those subtle dynamic shifts musicians use to express beauty and emotion – with nuanced alacrity. Bass instruments are presented with linearity, definition and control. True to its heritage, Lohengrin presents the weight and authority of the original event with grace and power. The sound is fresh, vibrant, and immersive, drawing listeners deeply into the music.

Building upon our signature foundation of dynamically expressive, authoritative sound, Lohengrin delivers extraordinary immediacy, drawing listeners inward, beyond mere sonic accuracy, toward something subtler and truer: the hidden intentions, elusive emotions, and unspoken truths musicians strive to convey.

Lohengrin — Open left and top side
Lohengrin angle
Lohengrin front
Lohengrin back

Functionality features

  1. Fully balanced differential input and driver stages for increased signal swing, bandwidth and stability
  2. Fully balanced differential circuit – single-ended signal produces balanced signal at output
  3. Zero global Negative Feedback
  4. Shorter, faster feedback loop for greater tonal control without phase shift.
  5. Ease in handling loudspeaker loads for greater signal stability
  6. The amplifier is unconditionally stable, without the need for any capacitor compensation
  7. Low impedance output stage for superior loudspeaker control
  8. Dramatically increased interleaving and coupling in the balanced VTL proprietary Reference output transformer, for wider bandwidth with zero ringing
  9. Variable user-adjustable DF feedback control to vary output impedance and damping factor for optimal matching to speaker load
  10. Precision-regulated Plate and Screen supplies
  11. Software microprocessor controlled
  • Tetrode/Triode Switchable
  • Auto Bias, Fault Sensing
  • Current in-rush limiting
  • Standby Mute function; with reduced tube current for increased tube life
  • Fully bi-directional RS-232 control
  1. 400 watts per channel in tetrode; 200 watts per channel in triode
  2. Utilizes eight 6550 or KT-88 tubes per monoblock
  3. Adjustable precision-regulated plate and screen supplies for stable output tube operating points; discrete regulated input and driver supply for greater signal resolution and tonality
  4. Adjustable precision-regulated bias supply for greater signal resolution and noise rejection and improved isolation from mains supply variations; output tube operating point does not change with normal AC power fluctuations
  5. Microprocessor-controlled automatic bias system and multiple redundant layers of comprehensive fault sensing to protect amplifier against output tube failure.
  6. All premium Mundorf silver oil caps in signal path
  7. Film bypass of power supply caps for greater HF resolution
  8. Extruded aluminum front panel with luxurious, new look and tube visual via viewing window. Optional black or silver cosmetic
  9. Rigid construction and improved ventilation for lower operating temperature

Documentation

pdficon_smallLohengrin Data Sheet

Technical Specifications

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)

Grail Quest…

“The Lohengrin’s ability to flow through the music’s rhythms, drive its beat and capture subtle differences in articulation brings the rhythmic patterns, the enthusiasm and the ‘danceability’ right to the fore.  Yes, there’s plenty of control and definition, but there’s nothing static or immobile about the pace, attack and musical energy projected by the Lohengrins.”

“… the Lohengrin/Alexia pairing is consummately musical, sonically impressive and downright charming! The only hard part was leaving the Lohengrin behind.  Back home I’m still waiting for my brain to readjust to what I’m missing.  This Lohengrin isn’t going anywhere.  It hasn’t just delivered on its promise, it’s reaching out for a permanent place amongst that select group of high-end amplifiers that are both capable and genuinely musical.  Definitely a defender of the Grail.”

Read the full review on gy8.eu website …

pdficon_smallFull review — PDF format

- Dennis Davis, Gy8@eu “Grail Quest: Listening to VTL’s latest, the Lohengrin mono-blocs”, January 16, 2026

Warsaw Premieres and Triumphs

“My best sounding room of Day 1, “an oasis of beauty and musicality,” showcased the latest prototype of the forthcoming (January 2026?) VTL Lohengrin monoblocks … On “Voodoo,” the title track from The Sonny Clark Memorial Quartet’s eponymous LP, the sound was open, clear, timbrally true, and gloriously alive and transparent. It was the aural equivalent of a breath of fresh air. Drums and cymbals sound exactly right, and it was easy to hear and feel the texture of the drum head. The sound was gorgeous—pure pleasure.”

Read more here …

- Jason Victor Serinus, Stereophile Warsaw Audio Show 2025 Show report, Oct 29, 2025