AGD Gran Vivace Monoblock

Design Philosophy

The AGD Gran Vivace Monoblock is the new addition to the AGD GanTubeTM Hi-End Power Amplifiers family. First to use the unique GaNTube™ technology with Gallium Nitride Power-Stage integrated into a Vacuum Tube, the AGD amplifiers are the most technologically advanced design available in the market today. The AGD “Gran Vivace” is rated 400W on 4ohm and it is characterized by an outstanding 50A peak output driving capability that will satisfy the most demanding loudspeakers and fill with musical sound pressure also the largest audio rooms. To achieve these performances, we have designed a new GaNTubeTM component, the AGD GaNTube KT120, larger and more powerful than its sibling AGD GaNTube KT88 MKii.

To achieve the highest-performance in audio reproduction, switching topologies must achieve nearly ideal switching waveforms, completely oscillation-free, to minimize distortion but most importantly, to preserve the harmonic content present in the original input signal and avoid the superimposition of any additional artifacts that alter the overall spectrum and the spatiality of the music reproduction. The Gallium Nitride power MOSFETS used in the GaNTubeTM power-stage simplifies this challenge through its ability to efficiently switch at much higher slew rates than any silicon-based power MOSFET, with almost perfect (book-like) behavior and oscillation free switching.

In this new AGD GaNTubeTM 120KT, a pair of powerful 600V rated Gallium-nitride power MOSFETs are at the core of the design. These new advanced components are the key to the reference level performance of the AGD “Gran Vivace” Monoblocks. Thanks to the improvement in components, and PCB layout (tested and introduced recently with the AGD GaNTubeTM KT88 MKii), we achieved the goal to operate also this much larger power-stage at 800kHz, with a direct and positive impact on the overall already outstanding sonic and musical performances.

Design Philosophy

With the seamless ability to drive any loudspeakers, 400W of power, 50A of peak current, 70,000µF of super audio grade capacitor reservoir, and the fastest slew-rate, the AGDKT120GaNTube standard with the Gran Vivace, can deliver an incredible immersive holographic powerful and pure musical experience.
Thanks to the new 600V high-current Gallium-Nitride power MOSFETs stage, the improved layout with enhanced thermal characteristics and the virtually stray-inductance free package, the rise time and fall time of the Gran Vivace’s KT120GaNTube power stage are fully symmetrical and oscillation-free, with dv/dt similar to the one offered by the smaller sibling AGDKT88 Mkii used in the AGD “The Audion” and AGD “Vivace” amplifiers.

The AGD “Gran Vivace” is designed with the specific goal to satisfy the most demanding Audiophiles with the most critical efficient loudspeakers and the larger audio rooms.

This oscilloscope snap-shot of the output power stage half-bridge switching node, is a dramatic evidence of the tremendous difference in switching speed between the Gallium Nitride Power MOSFET and the state of the art Silicon Power MOSFET equivalent.

The combination of low noise design technique implemented and the best practice for the internal board layout, the RF quality BNC connectors for the analog signals, are the key contributors of the excellent noise floor of the Vivace Monoblocks and extremely low distortion.

  • Switching node waveforms ~3000V/μs.
  • 125V switching peak-to-peak without overshoot or undershoot artifacts.
  • No undesired harmonic residuals or other artifacts are transferred to the output filter
  • New dual 600V GaN power MOSFET output stage switching at ~800kHz
  • Comparison between switching waveform at full voltage between GaN and Silicon based MOSFETs
  • GaN is ~10x faster that standard MOSFET
  • Output noise spectrum in µV vs. frequency ( no input signal)
  • FFT spectrum @ +3db output, 4ohm, 1kHz
  • XLR Input

AGD “Gran Vivace” Monoblock

The AGD “Gran Vivace” Monoblock retains the same industrial design pioneered with the “Vivace” model.

Its unique form with a blend of avant-garde touch industrial design, along with its leading-edge power electronics, all GaN-based, makes a superb Hi-End Audio amplifier that is capable to deliver an unprecedented powerful and incredible realistic audio reproduction experience.

The “Gran Vivace” incorporates several improvements and features intended to make the daily operation of the amps more user friendly, such as the additional stand-by remote switch (pressure sensitive) located on the front top surface of the chassis, and the convenient additional 12V trigger input for remote on-off/stand-by operation, located on the back side of the amplifier, next to the input selector switch.

Main Features & Characteristics

  • Single Channel Class-D Amplifier
  • Fully integrated into Glass Tube Enclosure
  • Gallium Nitride 600V MOSFET Power Stage
  • Up to 400W 4Ω (GaNTube 120KT model)
  • 800KHz PWM
  • ≥ 94% Efficiency
  • Noise floor at ≤ -130db
  • Fully protected (OVT, OVC, DC)

The AGD “Gran Vivace” has both balanced and RCA-inputs. The input source can be selected by the input selector switch placed on the back panel side. The amplifier unit can be turned ON-OFF (stand-by mode) via  +12V Remote input trigger (3.5mmJack).

The power entry module used for the AGD “Gran Vivace” is the same high-grade quality component with standard medical-grade EMI filter as the one used with the AGD “Vivace” model.

The speakers biding posts are WBT model and can handle cables of large cross sections.

Maximum Output Power (CEA-2006), 4Ω400W
THD+N 10W/1KHz<0.0075%
Signal to Noise ratio at 1kHz>110 db
Bandwidth ±0.5dB20Hz÷20KHz
Output Noise (A-weighted)≤ 45μV
PWM Frequency800kHz
Dynamic Range120dB
Dimension11"×11’x5" (279x279x127mm)
Weight22lbs (10kg)
Input Voltage110-240V (user selectable)