G-811 Monoblocks

G-811 Tube Amplifier Set – High-End Class A SE Stereo System

The G-811 is an exclusive SE (Single-Ended) Class A tube amplifier set offering exceptional sound quality and outstanding handmade craftsmanship. Designed and built in Latvia, this set consists of two monoblock amplifiers and a separate volume control unit, designed as a high-quality passive-active signal control stage. It provides stable and musical signal processing while preserving the natural character and dynamics of the sound. The volume control section uses an autotransformer, allowing precise adjustment of the signal level while maintaining excellent microdynamics and sonic energy. The unit also features two-input switching, allowing two different audio sources to be connected and conveniently selected.

Construction:

• Chassis:

  • Made from solid mahogany, solid zebrawood, solid oak and plywood, giving the units a natural aesthetic appearance and excellent durability.
  • Metal components complement the design with modern and elegant accents.

• Tubes:

  • Monoblocks:
    • Power stage: One Г-811 tube in each monoblock provides stable, dynamic power and a warm, engaging sound. Г-811 (read more  in our blog) is a powerful directly heated triode originally developed in the United States in the 1940s (the American equivalent being the 811/811A) for radio transmitters and high-frequency equipment. It was later widely manufactured in the Soviet Union and used in industrial and communications equipment. Today, the Г-811 is also found in high-power tube audio amplifiers, particularly in Single-Ended (SE) and, in some cases, Push-Pull configurations. In audio applications, this tube can provide relatively high output power compared with traditional audio triodes while retaining the characteristic linear operation and harmonic qualities of a triode.
    • Preamplifier stage:
      • One 6П6С tube provides precise and musical signal amplification. The 6П6С is the Soviet-era equivalent of the legendary 6V6 tube. The 6П6С tetrode was developed in the mid-20th century and was initially intended for military and professional equipment where high reliability, long service life and stable operation were required. These tubes were widely used in radio equipment, studio amplifiers and instrument amplifiers, particularly guitar amplifiers.
      • One EF86 (Tungsram) tube provides expressive harmonics, sensitivity and fine detail. The EF86 is a low-noise, high-gain pentode specifically developed for the amplification of audio-frequency signals. The EF86 was introduced in 1953 by the Philips/Mullard group and was subsequently manufactured by several European companies, including the Hungarian manufacturer Tungsram. Tungsram EF86 tubes were primarily produced from the mid-1950s through the 1970s in Budapest, Hungary, and gained a reputation as high-quality alternatives to tubes made by Western European manufacturers. The EF86 was designed as a dedicated preamplifier tube for high-quality audio equipment. Unlike many other pentodes, it was specifically engineered with low noise and reduced microphonics in mind. Its primary applications included amplifying very low-level audio signals in microphone preamplifiers, tape recorders, radio receivers, studio equipment and Hi-Fi amplifiers.
    • Rectifier: One EZ81 (Tesla) tube provides full-wave rectification in the power supply, contributing to stable and clean operation. The EZ81 is a full-wave vacuum-tube rectifier with two anodes that became particularly popular in Europe during the 1950s and 1960s. It was developed as a compact and reliable power-supply component for radios, tape recorders and tube audio amplifiers. EZ81 tubes manufactured by the Czechoslovak company Tesla are highly regarded today among vintage audio enthusiasts for their reliability and musical character. The EZ81 was developed by the Philips/Mullard group in the mid-1950s as part of the European Noval (B9A) miniature tube series. Tesla factories in Czechoslovakia began producing the tube in the late 1950s and continued manufacturing it for several decades, primarily at the Rožnov and other Tesla plants. Tesla tubes were widely used in Eastern European audio and radio equipment. The primary function of the EZ81 was to convert alternating current into direct current in the power supplies of tube equipment. It was intended for medium-power audio systems requiring a stable, relatively low-noise anode-voltage supply. Its indirectly heated cathode helped significantly reduce background noise and AC hum.
  • Volume Control Unit:
    • Two 6С3П-ЕВ tubes are used for signal processing in the volume control stage, providing clean, stable and musical operation while preserving the natural character and dynamics of the sound. The 6С3П-ЕВ is a miniature triode designed and manufactured in the Soviet Union, primarily during the second half of the 20th century. The “ЕВ” designation indicates an enhanced version with increased mechanical and operational reliability. Tubes of this type were widely used in professional communications equipment, measuring instruments, military electronics and other applications requiring stable operation and reliable signal performance. Today, the 6С3П-ЕВ is also appreciated in tube audio equipment for its distinctive sonic character and durability.
    • An autotransformer provides precise volume control while preserving excellent dynamics and sonic energy. Unlike a conventional potentiometer, the signal level is controlled through transformer coupling, allowing particularly smooth and natural volume adjustment while maintaining microdynamics.  Output transformers provide high-quality signal transfer to the power amplifier stage.
    • Two-input switching allows two different audio sources to be connected and conveniently selected.

Technical Specifications:

• Output power: 2 x 12 W – ideally suited to medium and large rooms when paired with high-sensitivity loudspeakers.
• Monoblocks:
  • Dimensions: Width 43 cm x Height 16 cm x Depth 35 cm
  • Weight: 18 kg each.
• Volume Control Unit:
  • Dimensions: Width 45 cm x Height 13 cm x Depth 27 cm
  • Weight: 10 kg .

Sound Quality:

The main strength of this tube amplifier set is its natural, spacious and harmonically rich sound, revealing the nuances of vocals, acoustic instruments and the recording environment. The Г-811 Single-Ended triode power stage provides an expressive and lively presentation with excellent microdynamics and the characteristic harmonic structure associated with triode amplification. The Г-811 power tube in each monoblock serves as the main source of sonic energy. Its character can be described as rich, fluid and highly musical. The midrange is particularly expressive: vocals gain body and presence, while guitars, strings, piano and wind instruments are reproduced with rich tonal nuances.

The 6П6С in the driver stage complements the system with a full and harmonically coherent presentation. It helps create a dense yet well-structured sound while preserving musical flow even in complex musical passages.

The Tungsram EF86, meanwhile, is a pentode well known in audio applications for its sensitivity and high-quality amplification characteristics. It contributes excellent signal detail and expressive microdynamics. The EF86 provides clean and nuanced amplification, allowing even the finest details of a recording to emerge.

The Tesla EZ81 rectifier gives the system an additional touch of classic tube technology. Since the power supply uses tube rectification, the power section complements the overall design philosophy of the amplifier. This creates a coherent, traditional tube-based architecture throughout both the signal and power-supply sections.

The use of two independent G-811 monoblocks allows each stereo channel to operate through its own dedicated power amplification stage. This contributes to excellent channel separation, a precise stereo image and a convincing sense of depth.

The volume control unit, equipped with two 6С3П-ЕВ tubes, extends the character of the tube signal path before the signal reaches the monoblock amplifiers. These highly reliable Soviet-era tubes provide stable operation and help maintain smooth and musical signal processing.

Combined with transformer-based volume control, this creates a distinctive signal-management solution. The autotransformer allows the listening level to be adjusted while preserving dynamics and avoiding the impression that music becomes flat or loses its energy as the volume is reduced.

Read more about the Г-811 triode here.